ExpandLinq: stop expanding Range().{ToArray()|ToList()}

These are already optimized in LINQ and vectorized in .NET 8, see #25

Author: dubiousconst282

src/DistIL/Passes/ExpandLinq.cs

@@ -43,16 +43,23 @@ public MethodPassResult Run(MethodTransformContext ctx)
 
     private static bool IsProfitableToExpand(LinqSourceNode source, LinqSink sink)
     {
-        //Unfiltered Count()/Any() is not profitable because we scan the entire source.
+        //Unfiltered Count()/Any() is not profitable because we always scan over
+        //the entire source, and LINQ specializes over collections and such. 
         if (sink.SubjectCall is { NumArgs: 1, Method.Name: "Count" or "Any" }) {
             return false;
         }
-        //Concretizing enumerator sources may not be profitable because 
+        //Expanding enumerator sources may not be profitable because 
         //Linq can special-case source types and defer to e.g. Array.Copy().
         //Similarly, expanding an enumerator source to a loop sink is an expansive no-op.
         if (source is EnumeratorSource && source.Drain == sink) {
             return sink is not (ConcretizationSink or LoopSink);
         }
+        //Range().ToArray() and ToList() are already special-cased by LINQ, and vectorized in .NET 8.
+        // - https://github.com/dubiousconst282/DistIL/issues/25
+        // - https://github.com/dotnet/runtime/pull/87992
+        if (source is IntRangeSource && source.Drain == sink) {
+            return sink is not ListOrArraySink;
+        }
         return true;
     }