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

[Trung Nguyen via llvm-commits]

trungnt2910 wrote:

The primary motivation is to move away from Microsoft tooling for my project (trungnt2910/lxmonika#9), especially as MSVC v145 in VS2026 dropped support for 32-bit ARM. 

One of my main goals is to make this driver works across all known Windows NT 10.0 builds, and it involves [using SEH](https://github.com/trungnt2910/lxmonika/blob/3f7b56c5af4b1228934c8379659946aae41b9f95/lxmonika/src/picosupport.cpp#L614) to dynamically determine how much data a certain kernel API expects without having to hard code Windows build numbers. 

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