Fix shrinking windows when suspending
When suspended, if a window is for some reason configured by the compositor, the compositor will likely send the bounds 0 x 0, which should be interpreted as "no particular bounds to report". However, in GTK this was still used in more or less a MAX (min_size, MIN (bounds, natural_size))
kind of way, which made affected windows shrink to their min sizes.
This merge request more or less changes the zeros to INT_MAX
so that we don't attempt to clamp when there is nothing to clamp to. In future configuration sequences, we'll still receive bounds, which GTK can react to.