Make sure uibench test app load list content

If the test app is relaunched by configuration change (e.g. the
testing device is put in landscape), the fragment will be kept
but its content needs to reload. Otherwise it will show a loading
animation that causes unexpected frame count.

This change makes ShadowGridActivity, ClippedListActivity,
MainActivity inherit CompatListActivity that sets new list adapter
to the existing fragment. So the list can show correct content.

Bug: 156473870
Test: atest UiBenchJankTests
Change-Id: Ie608baa7362642554c014f805c797d09f4cf3117