[clang] [llvm] [AArch64] Make user-visible Arm architecture version strings consistent (PR #98550)

[Jonathan Thackray via llvm-commits]

jthackray wrote:

> LGTM. Seems like there are still many more inconsistencies that could be improved too.

Yes, the more I looked through, the more I spotted. I'm aiming to get something merged before llvm19 branching, since these are (much more) user-visible now.

https://github.com/llvm/llvm-project/pull/98550