window-props: Also check for actual values change

Commit e28c1ab4 added a hints_have_changed() function to only
recalculate windows features when the WM_NORMAL_HINTS change.

That function hints_have_changed() however was merely checking whether
the various XSizeHints flags where flipped, which is not sufficient
because the hints may remain the same while the actual values are
changed.

Not checking for the actual value differences would prevent some windows
from being able to switch fullscreen.

Improve the helper function hints_have_changed() to check not only for
flags being flipped, but also for the values being changed for each
relevant XSizeHints flags being set currently.

Closes: https://gitlab.gnome.org/GNOME/mutter/-/issues/1534
(cherry picked from commit 06e604cf)

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1575>