Removing default display assumption on ApplicationTest.

Toggling the orientation of the activity will only trigger a
configuration change on the display that the activity is currently on.
This change toggles the font scale and is not dependent on which display
an activity is displayed on.

Bug: 70792582
Test: CTS builds, passes on phones and vr headsets.
Change-Id: I6eb465ab12534772b4afcb11cba1d68558ce850a
1 file changed