Support `-x` for clang-cl

`clang-cl -help` shows that `-x` is supported directly. It was added by #68921 to support CUDA/HIP. 

But `clang-cl -x c++-module` report an error
```
unsupported option '-x c++-module'; did you mean '/TC' or '/TP'?
```

Support `-x` for clang-cl, so that we can use `/clang:` to compile C++20 modules (#64118).
