present: Check that flip and screen pixmap pitches match

If they don't, flipping will result in corrupted display.

Test case:

* Run Xorg at 1920x1080 with no window manager
* glxgears -geometry 2048x1080

The Present extension code in xserver 1.21 will check for this.

Tested-by: Jax Lin <jax.lin@amd.com>
11 jobs for present_check_flip-pitch in 2 minutes and 13 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Build
passed xserver-1.13 #146078

00:00:23

passed xserver-1.14 #146079

00:00:24

passed xserver-1.15 #146080

00:00:38

passed xserver-1.16 #146081

00:00:24

passed xserver-1.17 #146082

00:00:24

passed xserver-1.18 #146083

00:00:24

passed xserver-1.18-clang #146084

00:00:47

passed xserver-1.19 #146085

00:00:24

passed xserver-1.19-clang #146086

00:00:26

passed xserver-1.20 #146076

00:00:32

passed xserver-1.20-clang #146077

00:00:27