This fixes the issue observed in ulyssa/iamb#307 where typing <C-W>o after restoring the window layout could reproducibly crash. The problem is that when the ResizeInfo contains window lengths (which it always does on restore, since they get snapshotted), they don't get cleared when WindowLayoutState::only is called. This results in an inconsistent state that the assertion in set_area_lens runs into later on.
This fixes the issue observed in ulyssa/iamb#307 where typing
<C-W>oafter restoring the window layout could reproducibly crash. The problem is that when theResizeInfocontains window lengths (which it always does on restore, since they get snapshotted), they don't get cleared whenWindowLayoutState::onlyis called. This results in an inconsistent state that the assertion inset_area_lensruns into later on.