Launch test activity in fullscreen in WindowInsetsControllerTests

WindowInsetsControllerTests#testInsetsDispatch is failing on cf_pc
because test activity is launched in freeform on cf_pc. When test
activity is launched in freeform, WindowInsetsController of the window
will not hide status bars and navigations because the window display
area does not overlap with the insets. Launch the test activity in
fullscreen so that system bars are hidden as expected.

Bug: 205887954
Test: atest WindowInsetsControllerTests
Change-Id: If1865c2e53048797087304ef1fa52fe7e252d099
1 file changed