[llvm] [X86][WinEH] Restore parent RSP before Win64 catchret continuation (PR #191616)

[Eli Friedman via llvm-commits]

https://github.com/efriedma-quic commented:

This looks basically right, although I haven't examined it in detail.

Please make sure we have test coverage for allocas with alignment greater than 16.

https://github.com/llvm/llvm-project/pull/191616