On non-AVX CPUs, CONTEXT_EX is not being initialized.
In WOW64 mode, this results in invalid exception records when
dispatch_wow_exception() uses RtlCopyContext().
Signed-off-by: Brendan Shanks <bshanks@codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>