[clang] [Driver] Remove a bunch of unnecessary REQUIRES constraints (PR #94055)

[Alexander Richardson via cfe-commits]

https://github.com/arichardson approved this pull request.

In the past I've cleaned up some local unnecessary REQUIRES: foo-registered-target in a downstream fork, good to see this being fixed upstream as well. I often build only a subset of targets so it's good to see more test coverage for that configuration.

https://github.com/llvm/llvm-project/pull/94055