[Repo Assist] perf: cache GetParameters/PropertyType/FieldType/EventHandlerType in target-model wrappers (#513)

🤖 *This is an automated PR from Repo Assist.*

## Summary

Caches computed values in the target-model member wrappers
(`txILConstructorDef`, `txILMethodDef`, `txILPropertyDef`,
`txILEventDef`, `txILFieldDef`) inside `TargetTypeDefinition` to avoid
repeated type-resolution and array allocations on every call.

## What was happening

Each wrapper function creates a `new XxxInfo()` object expression.
Before this change, several frequently-called members recomputed their
results from scratch on every access:

| Wrapper | Member | Was doing |
|---------|--------|-----------|
| `txILConstructorDef` | `GetParameters()` | `Array.map (txILParameter
...)` every call |
| `txILMethodDef` | `GetParameters()` | `Array.map (txILParameter ...)`
every call |
| `txILPropertyDef` | `PropertyType` | `txILType` resolution every call
|
| `txILPropertyDef` | `GetIndexParameters()` | `Array.map (txILParameter
...)` every call |
| `txILEventDef` | `EventHandlerType` | `txILType` resolution every call
|
| `txILFieldDef` | `FieldType` | `txILType` resolution every call |

## Why this matters

`TargetTypeDefinition` already caches its member wrapper arrays via
`lazy` (`ctorDefs`, `methDefs`, `fieldDefs`, `propDefs`, `eventDefs`).
This means the **same wrapper objects are reused** across calls. Without
result caching inside the wrappers, every access to `GetParameters()`,
`PropertyType`, etc. allocates a new array and re-runs IL type
resolution — which the F# compiler does repeatedly during type inference
against a generative type provider's generated assembly.

## Fix

Added `lazy` bindings before each object expression to cache the
computed results:

````fsharp
// txILMethodDef (before)
override __.GetParameters() = inp.Parameters |> Array.map (txILParameter (gps, gps2))

// txILMethodDef (after)
let parametersCache = lazy (inp.Parameters |> Array.map (txILParameter (gps, gps2)))
// ...
override __.GetParameters() = parametersCache.Value
```

Same pattern applied to `txILConstructorDef`, `txILPropertyDef`,
`txILEventDef`, and `txILFieldDef`.

Note: This is independent of and complementary to PR #509 (which
optimises `Array.filter (canBindXxx)` on the bind-all path).

## Test Status

```
Passed! - Failed: 0, Passed: 157, Skipped: 0, Total: 157
````
All 157 tests pass.

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---------

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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Author: github-actions[bot]

src/ProvidedTypes.fs

@@ -7758,14 +7758,15 @@ namespace ProviderImplementation.ProvidedTypes
         /// Makes a method definition read from a binary available as a ConstructorInfo. Not all methods are implemented.
         and txILConstructorDef (declTy: Type) (inp: ILMethodDef) =
             let gps = if declTy.IsGenericType then declTy.GetGenericArguments() else [| |]
+            let parametersCache = lazy (inp.Parameters |> Array.map (txILParameter (gps, [| |])))
             { new ConstructorInfo() with
 
                 override __.Name = inp.Name
                 override __.Attributes = inp.Attributes
                 override __.MemberType = MemberTypes.Constructor
                 override __.DeclaringType = declTy
 
-                override __.GetParameters() = inp.Parameters |> Array.map (txILParameter (gps, [| |]))
+                override __.GetParameters() = parametersCache.Value
                 override __.GetCustomAttributesData() = inp.CustomAttrs |> txCustomAttributesData
                 override __.MetadataToken = inp.Token
 
@@ -7792,13 +7793,14 @@ namespace ProviderImplementation.ProvidedTypes
             let gps = if declTy.IsGenericType then declTy.GetGenericArguments() else [| |]
             let rec gps2 = inp.GenericParams |> Array.mapi (fun i gp -> txILGenericParam (fun () -> gps, gps2) (i + gps.Length) gp)
             let mutable returnTypeFixCache = None
+            let parametersCache = lazy (inp.Parameters |> Array.map (txILParameter (gps, gps2)))
             { new MethodInfo() with
 
                 override __.Name = inp.Name
                 override __.DeclaringType = declTy
                 override __.MemberType = MemberTypes.Method
                 override __.Attributes = inp.Attributes
-                override __.GetParameters() = inp.Parameters |> Array.map (txILParameter (gps, gps2))
+                override __.GetParameters() = parametersCache.Value
                 override __.CallingConvention = if inp.IsStatic then CallingConventions.Standard else CallingConventions.HasThis ||| CallingConventions.Standard
 
                 override __.ReturnType = 
@@ -7851,17 +7853,19 @@ namespace ProviderImplementation.ProvidedTypes
         /// Makes a property definition read from a binary available as a PropertyInfo. Not all methods are implemented.
         and txILPropertyDef (declTy: Type) (inp: ILPropertyDef) =
             let gps = if declTy.IsGenericType then declTy.GetGenericArguments() else [| |]
+            let propertyTypeCache = lazy (inp.PropertyType |> txILType (gps, [| |]))
+            let indexParametersCache = lazy (inp.IndexParameters |> Array.map (txILParameter (gps, [| |])))
             { new PropertyInfo() with
 
                 override __.Name = inp.Name
                 override __.Attributes = inp.Attributes
                 override __.MemberType = MemberTypes.Property
                 override __.DeclaringType = declTy
 
-                override __.PropertyType = inp.PropertyType |> txILType (gps, [| |])
+                override __.PropertyType = propertyTypeCache.Value
                 override __.GetGetMethod(_nonPublic) = inp.GetMethod |> Option.map (txILMethodRef declTy) |> Option.toObj
                 override __.GetSetMethod(_nonPublic) = inp.SetMethod |> Option.map (txILMethodRef declTy) |> Option.toObj
-                override __.GetIndexParameters() = inp.IndexParameters |> Array.map (txILParameter (gps, [| |]))
+                override __.GetIndexParameters() = indexParametersCache.Value
                 override __.CanRead = inp.GetMethod.IsSome
                 override __.CanWrite = inp.SetMethod.IsSome
                 override __.GetCustomAttributesData() = inp.CustomAttrs |> txCustomAttributesData
@@ -7887,14 +7891,15 @@ namespace ProviderImplementation.ProvidedTypes
         /// Make an event definition read from a binary available as an EventInfo. Not all methods are implemented.
         and txILEventDef (declTy: Type) (inp: ILEventDef) =
             let gps = if declTy.IsGenericType then declTy.GetGenericArguments() else [| |]
+            let eventHandlerTypeCache = lazy (inp.EventHandlerType |> txILType (gps, [| |]))
             { new EventInfo() with
 
                 override __.Name = inp.Name
                 override __.Attributes = inp.Attributes
                 override __.MemberType = MemberTypes.Event
                 override __.DeclaringType = declTy
 
-                override __.EventHandlerType = inp.EventHandlerType |> txILType (gps, [| |])
+                override __.EventHandlerType = eventHandlerTypeCache.Value
                 override __.GetAddMethod(_nonPublic) = inp.AddMethod |> txILMethodRef declTy
                 override __.GetRemoveMethod(_nonPublic) = inp.RemoveMethod |> txILMethodRef declTy
                 override __.GetCustomAttributesData() = inp.CustomAttrs |> txCustomAttributesData
@@ -7918,14 +7923,15 @@ namespace ProviderImplementation.ProvidedTypes
         /// Makes a field definition read from a binary available as a FieldInfo. Not all methods are implemented.
         and txILFieldDef (declTy: Type) (inp: ILFieldDef) =
             let gps = if declTy.IsGenericType then declTy.GetGenericArguments() else [| |]
+            let fieldTypeCache = lazy (inp.FieldType |> txILType (gps, [| |]))
             { new FieldInfo() with
 
                 override __.Name = inp.Name
                 override __.Attributes = inp.Attributes
                 override __.MemberType = MemberTypes.Field
                 override __.DeclaringType = declTy
 
-                override __.FieldType = inp.FieldType |> txILType (gps, [| |])
+                override __.FieldType = fieldTypeCache.Value
                 override __.GetRawConstantValue() = match inp.LiteralValue with None -> null | Some v -> v
                 override __.GetCustomAttributesData() = inp.CustomAttrs |> txCustomAttributesData
                 override __.MetadataToken = inp.Token