Migrate all tests to ActivityTest.

ActivityInstrumentationTestCase2 takes care of starting and closing
the activity, which prevents flakyness.

Change-Id: I2d3908f6605a67a3c2d11e18a9c4799443828df9
(cherry picked from commit e366886c7d91b62fe1478a057fc4c0a104d12b02)
8 files changed