[clang][driver] Emit an error for `/clang:-x`

`/clang:-x` emits an error instead of a warning. And if the error is suppressed,
`/clang:-x` takes no effect.
Considering that `/clang:` is a recent addition in 2018-11 and there are MSVC
style alternatives, therefore `/clang:-x` doesn't seem useful and we just reject
it since properly supporting it would add lots of complexity.

Fixes #59307

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D142757