[llvm] [SystemZ] Add shrink-wrapping support for ELF prologue/epilogue (PR #225240)

[via llvm-commits]

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MarkVeerasingam wrote:

Resolved. Thanks for the help on this one Uli. Updated the code to use `canUseAsEpilogue`!
I didnt model Intels `flagsNeedToBePreservedBeforeTheTerminators` helper function. Within `canUseAsEpilogue` I added checks for `MBB.terminators` and `MBB.successors` 

https://github.com/llvm/llvm-project/pull/225240