Blender Git Loki

Fix sculpt transform incorrently flipping displacement in Y and Z axis

These functions were only checking the X axis for flipping the
displacement for a symmetry area depending on the initial position of
the pivot.
This affects transform and any other tools that transform vertices and
applies symmetry based on areas (the pose brush, for example).

Reviewed By: sergey

Differential Revision: https://developer.blender.org/D9654