Merge pull request dotnet/coreclr#19296 from mikedn/cast-cg

Refactor integer cast codegen

Commit migrated from https://github.com/dotnet/coreclr/commit/748b5a0a5a701b7f9803021313c620413e353fdc

diff --cc src/coreclr/src/jit/codegen.h
Simple merge

diff --cc src/coreclr/src/jit/codegenlinear.cpp
Simple merge

diff --cc src/coreclr/src/jit/codegenxarch.cpp
Simple merge