[llvm] Check for all frame instructions in finalize isel. (PR #85945)

[Matt Arsenault via llvm-commits]

https://github.com/arsenm approved this pull request.

The change itself is fine but your description of the problem sounds like there's an iteraction bug where the finalizeisel isn't resuming after a block split in the correct point. Is the SystemZ implementation of EmitInstrWithCustomInserter splitting the block incorrectly, or returning the wrong MBB pointer? 

https://github.com/llvm/llvm-project/pull/85945