[clang] [WebAssembly] Disable running `wasm-opt` on components (PR #98373)

[Alex Crichton via cfe-commits]

alexcrichton wrote:

Is there a way to "fake" a `wasm-opt` executable? I didn't find any existing tests for the `wasm-opt` integration and it's auto-disabled if `wasm-opt` isn't found on `$PATH`, which doesn't happen by default in the test suite, so unless I can set up `wasm-opt` to show up in `$PATH` as part of the test I'm not sure how to test

https://github.com/llvm/llvm-project/pull/98373