SSE: fix Mask::operator== by not using ptest
SSE: fix Mask::operator== by not using ptest

The _mm_testc_* intrinsic doesn't do the right thing for all compares.
Therefore use the movemask compare.

refs #684

Signed-off-by: Matthias Kretz <372ea4eca737a13cd010ee806d4ce7b98ee71550@kde.org>

chr-engwer/Vc,VcDevel/Vc,VcDevel/Vc,VcDevel/Vc,chr-engwer/Vc,VcDevel/Vc,chr-engwer/Vc