[clang] [llvm] [BPF] Lower unwinding to unwind_goto and unwind_exit (PR #233140)

[Kumar Kartikeya Dwivedi via cfe-commits]

kkdwvd wrote:

My bot found one issue, that might require setting r2 = 0 in addition to r0 for unwind_exit. https://gist.github.com/kkdwvd/1415b753b5346c72327dd56c84dce032. Otherwise looks great!

https://github.com/llvm/llvm-project/pull/233140