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

[Tom Stellard via llvm-commits]

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

Let's merge this now, because this test is failing on the release branch and blocking the release.  We can always clean up the test and remove the  version check in a  later commit.

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