New FlickerTests: Create initial flicker tests for Pip

Create an initial set of tests for pip. Initial tests are:
- All regions covered
- Status and navigation bar is always visible
- Pip window is shown, expanded, closed, and doesn't flicker
- Pip layer is shown, expanded, closed, and doesn't flicker
- Background is displayed behind Pip window

Test: atest FlickerTests:PipToHomeTest and atest FlickerTests:PipToAppTest
Change-Id: I16345de39a799744b97a5390495538d568693222