MSVC 2013: Compute uno bridge exception offset for X64

Change-Id: I34b308db422d861098fdf93cff8fea63128ba47a
Reviewed-on: https://gerrit.libreoffice.org/13211
Tested-by: David Ostrovsky <david@ostrovsky.org>
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>