[EXE] test: add vision_test

This test covers a few vision bugs:

1. VisibilityInStraightLineOfSight - test case checks the visibility
   of objects in a straight line of sight parallel to the X or Y
   coordinate lines:
   diasurgical/DevilutionX#7901

2. NoVisibilityThroughAdjacentTiles - test case checks that nothing is
   visible through the diagonally adjacent tiles:
   diasurgical/DevilutionX#7920

3. VisibleObjects - generic test, which makes sure some objects are
   visible, but some - are not.

Signed-off-by: Roman Penyaev <r.peniaev@gmail.com>

Author: artifacts-storage