[WinEH] Fill out .xdata for catch objects

[WinEH] Fill out .xdata for catch objects

This add support for catching an exception such that an exception object
available to the catch handler will be initialized by the runtime.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234062 91177308-0d34-0410-b5e6-96231b3b80d8