[clang] [llvm] [ARM] Add support for Windows SEH (PR #184953)

[Trung Nguyen via cfe-commits]

trungnt2910 wrote:

Neither am I; I would appreciate any help on this.

This patch was AI-assisted, but I have reviewed each line of code, and I am happy to discuss the changes in depth.

I have tried building binaries with different `__try`/`__catch`/`__finally` combinations. I also tried linking `clang`-generated binaries with VS2022 MSVC ARM objects/shared libraries; unwinding across these functions all worked as expected on 32-bit ARM Windows 10.

https://github.com/llvm/llvm-project/pull/184953