tests/gem_tiling_max_stride: Add a test for max fence stride

tests/gem_tiling_max_stride: Add a test for max fence stride

gem_tiling_max_stride writes a data pattern to an X-tiled buffer using
the maximum supported stride, reads the data back as linear, and
verifies that the data didn't get scrambled on the way.

The test also checks that some invalid stride values are rejected
properly.

v2: Check invalid strides
v3: Check invalid stride with Y-tiling
    Include a few more invalid stride values
    Fix gen3 X-tile size
v4: A few more invalid strides :)
    Drop the useless memset()

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>