[clang] [llvm] [FMV][AArch64] Allow user to override version priority. (PR #150267)

[Alexandros Lamprineas via llvm-commits]

labrinea wrote:

The -O3 on the clang test seems to have different behavior on different hosts. My intention was to run an integration test which will use llvm's globalopt pas, but there's no need. We have unittests for it. I'll modify and regenerate the test.

https://github.com/llvm/llvm-project/pull/150267