[test] Make CenteredEdgesTest more reliable

On some environment, the x delta is of 2 pixels:
CenteredEdgesTest.testArrangeAllOnStraightEdges-->Wrong edge source
connection: expected Point(411.0, 130.0), but was Point(409.0, 130.0).
This is probably because the snap to grid is enabled on this test.

Change-Id: Idde013ed148e20a51d335c6f3fbb94e04e6661e9
Signed-off-by: Laurent Redor <laurent.redor@obeo.fr>
1 file changed