MS ABI x64: Don't destroy arguments twice on x64

We were destroying them in the callee, and then again in the caller.  We
should use an EH-only cleanup and disable it at the point of the call
for win64, even though we don't use inalloca.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@207733 91177308-0d34-0410-b5e6-96231b3b80d8