Revert "[SimplifyCFG] Stop inserting calls to llvm.trap for UB"

This reverts commit r273778, it seems to break UBSan :/

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@273779 91177308-0d34-0410-b5e6-96231b3b80d8
10 files changed