Merge pull request #15527 from everton1984:faster_acc

* Adding support for vectorized masking for uchar/ushort.

* Fixing bug where mask was zeroing the dst. Improved the way to calculate
the mask and tweaked for further performance improvements.

* Fixing mask comparison test.

* Restricting to one channel.

* Adding support for 3 channels, switch old approach to start using HAL's
v_select.