Revert "wayland: Avoid pointer warp if constraint region is invalid"

This reverts commit 7c91c4ba.

It created regressions in some video games. After a closer look at the
pointer constraint region handling, there are some issues, but it might
be safer to fix them in master.

In meanwhile, let's revert 7c91c4ba because it breaks more things than
it fixes.

CCBUG: 457021
BUG: 469555


(cherry picked from commit 07da1796)