FlickerTests: Fit system windows properly

Also remove CUTOUT_MODE_SHORT_EDGES from flicker tests

This is a tripping hazard because the runtime attempt to set this
mode doesn't do anything. Just make all the activity layouts fit
system windows.

Test: atest com.android.wm.shell.EnterSplitScreenByDragFromNotificationGesturalNavPortrait
Test: atest FlickerTestsRotation
Test: atest FlickerTestsAppLaunch
Test: atest FlickerTestsNotification
Bug: 400479142
Bug: 398918267
Flag: EXEMPT test
Change-Id: I04864aba7587061144386e5ddfcb3ec0334d8f6c