[llvm] [BOLT][AArch64] Refuse to run Stoke analysis on AArch64 (PR #195878)

[Paschalis Mpeis via llvm-commits]

https://github.com/paschalis-mpeis approved this pull request.

> Nit: should it be "It is fundamentally a X86 pass" in the commit description?

Good call. I see that in the unsupported tests file, we now separate the passes specific to X86. That's nice. Maybe we could adjust the message a bit? 

```diff
- BOLT-ERROR: stoke-get-stat is supported only on X86
+ BOLT-ERROR: stoke-get-stat is specific to X86
```


Would the above make things clearer? (similarly for CMOV, etc)

https://github.com/llvm/llvm-project/pull/195878