[llvm] [CodeGen] Remove `applySplitCriticalEdges` in `MachineDominatorTree` (PR #97055)

[Nikita Popov via llvm-commits]

nikic wrote:

Reverted due to large compile-time regressions, see http://llvm-compile-time-tracker.com/compare.php?from=cb3bc5be9c20d893adf94cdf436092657ab5ab40&to=c5e5088033fed170068d818c54af6862e449b545&stat=instructions:u.

https://github.com/llvm/llvm-project/pull/97055