Reworked adders and tests (#878)

Added and reworked all adders and helper operations. Adders supported:

* General in-place adder `IncByLE`. Implemented via TTK adder. Specific
implementations:
   * `RippleCarryTTKIncByLE`
   * `RippleCarryCGIncByLE`
   * `FourierTDIncByLE`
* General `IncByI`. Implemented via
`IncByIUsingIncByLE(RippleCarryTTKIncByLE)`.
* General `IncByL` implemented via
`IncByLUsingIncByLE(RippleCarryTTKIncByLE)`.
* General out-of-place adder `AddLE`. Implementated via CG adder.
Specific implementations:
   * `RippleCarryCGAddLE`
   * `LookAheadDKRSAddLE`
* Helper function `IncByLEUsingAddLE` to use two out-of-place adders to
add in-place.
* Helper function `IncByIUsingIncByLE` to increase by Int using an
in-place adder.
* Helper function `IncByLUsingIncByLE` to increase by BigInt using an
in-place adder.

TTK adder updated to reduce simulation time by ~7%, CG adder updated to
reduce simulation time by ~30%.

Added and unified tests.

All adders are now in the Microsoft.Qunatum.**Unstable**.Arithmetic
namespace to signify that they will change in future and will be moved
to a separate library when we have support for it.
Note that we will entirely remove Microsoft.Qunatum.Arithmetic namespace
from the standard library by moving a few remaining operations to a
different namespace where they fit better. This will be in a separate
PR.

---------

Co-authored-by: Dmitry Vasilevsky <[email protected]>

Author: DmitryVasilevsky

compiler/qsc_frontend/src/compile.rs

@@ -397,10 +397,6 @@ pub fn std(store: &PackageStore, target: TargetProfile) -> CompileUnit {
                 "arithmetic.qs".into(),
                 include_str!("../../../library/std/arithmetic.qs").into(),
             ),
-            (
-                "arithmetic_internal.qs".into(),
-                include_str!("../../../library/std/arithmetic_internal.qs").into(),
-            ),
             (
                 "arrays.qs".into(),
                 include_str!("../../../library/std/arrays.qs").into(),
@@ -445,6 +441,14 @@ pub fn std(store: &PackageStore, target: TargetProfile) -> CompileUnit {
                 "random.qs".into(),
                 include_str!("../../../library/std/random.qs").into(),
             ),
+            (
+                "unstable_arithmetic.qs".into(),
+                include_str!("../../../library/std/unstable_arithmetic.qs").into(),
+            ),
+            (
+                "unstable_arithmetic_internal.qs".into(),
+                include_str!("../../../library/std/unstable_arithmetic_internal.qs").into(),
+            ),
         ],
         None,
     );