[clang] Add flag to opt out of wasm-opt (PR #95208)

[Dan Gohman via cfe-commits]

sunfishcode wrote:

@mh4ck-Thales A warning could be useful in some situations, but I also don't know how to navigate the situation with existing users using `-Werror`.

@sbc100 I'm open to ideas for how to limit the scope to wasm in some way.

https://github.com/llvm/llvm-project/pull/95208