Use the correct class handle for fat call temporary (dotnet/coreclr#9893)

Use the correct class handle for fat call temporary (dotnet/coreclr#9893)

`clsHnd` is the class handle of the type that owns the method for
`opcode != CEE_CALLI`. We need the class handle for the method's
return type though.

This is ending up with RyuJIT asking weird questions over JitInterface
(`getClassGClayout` of a reference type).

Also removing a line that was added in dotnet/coreclr#9191 to support the old code.

Commit migrated from https://github.com/dotnet/coreclr/commit/58010850217463943ba5910ddc8303b9d36f709e