Move two DocumentsTest form factor checks to host

Device-side tests were attempting to skip themselves but some of
the test runners do additional processing after the end of the
test. We need to propagate the assumption violated exception up
to let the test know to exit early.

This is used by TV, Auto, and Wear targets to gate the tests for
some DocumentsUI-related bits of CTS.

Test: atest android.appsecurity.cts.DocumentsTest
Bug: 158034056
Change-Id: I0fe2871a54e8c74769b7feba47f7142f13b8b63e
1 file changed