SF: add a backdoor to introduce a janky frame to HWC

Bug: 346503493
Test: adb shell service call SurfaceFlinger 1046 i32 3Test: adb root && adb shell service call SurfaceFlinger 1046 i32 3
Flag: EXEMPT bugfix
Change-Id: Ic4a837ef06aca40a24db9c1121e19e3e1a1e0d80
6 files changed