Add FlakyTest annotation to unblock presubmit

Also move the non-flaky test back to presubmit.

Fix: 263148628
Bug: 263213649
Test: atest WMShellFlickerTests:DragDividerToResize
Change-Id: I2065ae54d536bf7a7eabdb7a920edc76fe32aeb9
1 file changed