[llvm] [BOLT][AArch64] Check Last Element Instead of Returning `nullptr` in `lookupStubFromGroup` (PR #114015)

[Paschalis Mpeis via llvm-commits]

paschalis-mpeis wrote:

Thanks @liusy58  that is some fast action!

Not sure if I'm missing something, I still see the file as `bolt/test/AArch64/one-stub.s`.
Since you are still at it, you may remove `-nostdlib` from RUN line 6.

https://github.com/llvm/llvm-project/pull/114015