Migrate some CTS tests about PIP presentation to WMShellFlickerTests

Test mappings are as follows:
- testPinnedStackInBoundsAfterRotation => PipRotationTest
- testEnterPipToOtherOrientation => PipOrientationTest
- testSetRequestedOrientationWhilePinned => PipOrientationTest
- testPinnedStackWithDockedStack => PipSplitScreenTest
- testDisplayMetricsPinUnpin => EnterExitPipTest

Some other accompanying changes are as follows:
- add FixedAppHelper for FixedActivity.
- add testapp.Components to provide the constants for each test app.
- extend PipActivity to accept some extras from Intent/BroadcastIntent.

Bug: 161980624
Test: atest WMShellFlickerTests
Change-Id: I64d97a51387370cc086c9dcdded846e4a8c1c0ea