[Dominators] Invalidate DFS numbers upon edge deletions

This patch makes DeleteEdge correctly invalidate DFS numbers in the
incremental updater. This should fix PR34466 and related bugs.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@314254 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed