The new line collision search uses BBox() to check for colliding
objects. BBox in the SHAPE_LINE_CHAIN did not include width as the
chains were assumed to be zero-width. This is not the case for
PNS::LINE elements.
We mostly don't notice this because DRC checks for SEGMENT collisions
but it becomes obvious/annoying when we cannot place a track for unknown
reasons and the snap-back doesn't take line width into account.
Fixes#3776 | https://gitlab.com/kicad/code/kicad/issues/3776
(cherry picked from commit fe15511d38)
9e6b56d783