Inline nodes in our layout tree have a position, so let's show it. By
centralizing the logic for this, block nodes now lose their redundant
'content-size' dump info which is already part of the box model dump.
In 89ba00304c, the box' X position was
capped at 0 to prevent negative X positions to act as if there were
intruding floats on the left side. Instead, we need to check whether the
left side float intrusion we are going to calculate matters at all -
because if there's no matching float box, the intrusion is always going
to be 0 and we don't need to take the box' X position into account.
Fixes the floating publication images on https://lexfridman.com/.