Recent change (CL 10370) unexpectedly broke TestRaiseException on
Windows XP amd64. I still do not know why. But reverting old
CL 8165 fixes the problem.

This effectively makes Windows XP amd64 use AddVectoredContinueHandler
instead of SetUnhandledExceptionFilter for exception handling. That is
what we do for all recent Windows versions too.

Fixes #11481

Change-Id: If2e8037711f05bf97e3c69f5a8d86af67c58f6fc
Reviewed-on: https://go-review.googlesource.com/11888
Run-TryBot: Alex Brainman <alex.brainman@gmail.com>
Reviewed-by: Daniel Theophanes <kardianos@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>