[WinEH] Run cleanup handlers when an exception is thrown

[WinEH] Run cleanup handlers when an exception is thrown

Generate tables in the .xdata section representing what actions to take
when an exception is thrown.  This currently fills in state for
cleanups, catch handlers are still unfinished.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233636 91177308-0d34-0410-b5e6-96231b3b80d8