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

[Alexander Yermolovich via llvm-commits]

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@@ -0,0 +1,32 @@
+# This test verifies that no unnecessary stubs are inserted when each DotAddress increases during a lookup.
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ayermolo wrote:

super minor nit I believe llvm code now wants ## for comments.

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