[llvm] [clang] [ARM] Introduce the v9.5-A architecture version to Arm targets (PR #78994)

[Lucas Duarte Prates via cfe-commits]

pratlucas wrote:

The ARM Target Parser is behind the AArch64 one in terms of design and refactoring. For the ARM case that relationship is not explicitly encoded in a single place, there are multiple switch-cases covering specific scenarios instead (e.g. the ones updated by this patch in clang/lib/Basic/Targets/ARM.cpp).

I've added a comment only to the TableGen file for now, at least until we get the ARM target parser to the same standards as the AArch64 one.

https://github.com/llvm/llvm-project/pull/78994