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

[Paschalis Mpeis via llvm-commits]

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@@ -0,0 +1,28 @@
+# REQUIRES: system-linux, asserts
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paschalis-mpeis wrote:

Consider adding a very short description, like how with this patch only creates one hot stub and re-uses for the 2nd call.

Maybe renaming `func` to `cold_func` could help future readers.

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