[WinEH] Tweak funclet prologue/epilogue insertion to pass verifier

For some reason we'd never run MachineVerifier on WinEH code, and you
explicitly have to ask for it with llc. I added it to a few test cases
to get some coverage.

Fixes PR25461.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@252512 91177308-0d34-0410-b5e6-96231b3b80d8
6 files changed