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

[Kamil Jakubus via llvm-commits]

jkbz64 wrote:

>The first thing WebAssemblyFixIrreducibleControlFlow::makeSingleEntryLoop does in debug/assertions builds is make sure the blocks after sorted by number are all valid (not -1) and unique.

I think the concern was for the newly created blocks inside the same function AFTER the assert, line 419 and line 504.

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