[llvm] [WebAssembly] Replace Reachability with SCCs in Irreducible CFG Fixer (PR #179722)

[Derek Schuff via llvm-commits]

https://github.com/dschuff commented:

Meanwhile we ran this against our internal tests and I also ran against the LLVM testsuite tests, and they all passed, so I'm feeling pretty good about this now. It does also seem to result in faster compiles.

https://github.com/llvm/llvm-project/pull/179722