Fix some WM unit tests

WindowFrameTests#testLayoutNonfullscreenTask and
sizes because test assumed that frame for window was always
bigger than screen size. Now we calculate all frames relative
to real display size.

TestWindowManagerPolicy used in WM unit tests reported incorrect
value from rotationHasCompatibleMetricsLw(), which lead to
DisplayContent#mAltOrientation set to "true" after any rotation
and resulted in shrinked display metrics.

DisplayContentTests#testDefaultDisplayOverrideConfigUpdate was
not restoring the config applied to default display because
it was trying update values in config from non-empty to empty,
which is considered a no-diff.

Test: com.android.server.wm.WindowFrameTests
Test: #testCalculatePolicyCrop
Test: #testLayoutNonfullscreenTask
Test: com.android.server.wm.AppWindowTokenTests
Test: #testLandscapeSeascapeRotationByApp
Test: com.android.server.wm.DisplayContentTests
Test: #testDefaultDisplayOverrideConfigUpdate
Change-Id: Ia0ed46307f67f6b47859209ebcf13253b59b8002