[llvm] Change check for embedded llvm version number to a regex to make test more flexible. (PR #79528)

[via llvm-commits]

dyung wrote:

> It would probably be better just to remove this check. I don't know why we would need to check the compiler version in the test.

I agree, but if we do need to keep the check, we should at least make it a regex. Or if the version should match something else, then the test should be rewritten to do that.

https://github.com/llvm/llvm-project/pull/79528