ci: Enable windows tests for 9.6.3

There were two failing tests:

1. CCompilerOverride, was attempting to use gcc.exe rather than
   clang.exe without also overriding the C options which led to
   incorrect options being passed to gcc.exe. The fix is to override to
   clang.exe on ghc-9.4 or newer.
2. ForeignLibs exposes a bug in GHC
   (ghc/ghc#24185) and hence is
   skipped for GHCs newer than 9.4 where it was first introduced.

Towards fixing #8451, we just need to fix the shared library issue now.