JIT: move indirect call transformations to a new source file (dotnet/coreclr#21414)

Follow-up from a review comment in dotnet/coreclr#21270.

Commit migrated from dotnet/coreclr@6e9c14e

Author: AndyAyersMS

src/coreclr/src/jit/CMakeLists.txt

@@ -40,6 +40,7 @@ set( JIT_SOURCES
   hashbv.cpp
   hwintrinsic.cpp
   hostallocator.cpp
+  indirectcalltransformer.cpp
   importer.cpp
   inline.cpp
   inlinepolicy.cpp