[llvm] [WebAssembly] Optimize `WebAssemblyCFGSort`'s post sort verifications. (PR #182458)

[Demetrius Kanios via llvm-commits]

QuantumSegfault wrote:

The alternative is to just gate this behind `EXPENSIVE_CHECKS` (or possibly do both).

Not entirely sure this makes all the same guarantees rigorously.

https://github.com/llvm/llvm-project/pull/182458