Add basic support for folding and normalizing hwintrinsic trees in morph (#103143)

* Add basic support for folding hwintrinsic trees in morph

* Reduce the amount of copying required to evaluated vector constants

* Have gtFoldExprHWIntrinsic handle side effects

Author: tannergooding

src/coreclr/jit/compiler.h

@@ -3649,6 +3649,10 @@ class Compiler
     GenTree* gtFoldTypeCompare(GenTree* tree);
     GenTree* gtFoldTypeEqualityCall(bool isEq, GenTree* op1, GenTree* op2);
 
+#if defined(FEATURE_HW_INTRINSICS)
+    GenTree* gtFoldExprHWIntrinsic(GenTreeHWIntrinsic* tree);
+#endif // FEATURE_HW_INTRINSICS
+
     // Options to control behavior of gtTryRemoveBoxUpstreamEffects
     enum BoxRemovalOptions
     {