[clang] [llvm] Fix Windows EH IP2State tables (remove +1 bias) (PR #144745)

[Arthur Eubanks via cfe-commits]

aeubanks wrote:

> Maybe we should make the compiler insert a nop after inline asm blocks marked "unwind"? Shifting the burden to the user seems error-prone, and the extra nop is unlikely to matter much.

@sivadeilra ping on this suggestion, can we do this instead of having users manually add the nop?

https://github.com/llvm/llvm-project/pull/144745