cmd/link: add more clang driver flags when testing flag [freeze exception]

[cerisier]

This is a request for a freeze exception for https://go-review.googlesource.com/c/go/+/730561.

Patch https://go-review.googlesource.com/c/go/+/730561 implemented #76825 via #76858, adds more clang driver configuration flags to the list of allowed flags used when testing if a particular flag is supported by the external linker.
The linker behaviour is changed only if those flags are passed.

Given the small size and low risk of the change, I think that it's worth giving https://go-review.googlesource.com/c/go/+/730561 a freeze exception to support fully hermetic LLVM-only toolchains when cross-compiling CGO.

[gabyhelp]

Related Issues

• cmd/go: GOEXPERIMENT=gocacheprog [freeze exception] #60419 (closed)

Related Code Changes

• cmd/link: add more clang driver flags when testing flag
• cmd/link: ensure that the "--target" clang flag is considered when testing for C linker capabilities

_{(Emoji vote if this was helpful or unhelpful; more detailed feedback welcome in this discussion.)}

[mknyszek]

CC @golang/compiler @golang/release