[llvm] [Demangler] support demangling for AIX function entry names (PR #67389)

[James Henderson via llvm-commits]

jh7370 wrote:

This work already has an ongoing review at https://reviews.llvm.org/D139864 by @diggerlin. We don't need this PR - please close it.

https://github.com/llvm/llvm-project/pull/67389