[Magnifier - 19] Add non-basic CTS tests

This CL adds two @TestApis required for the magnifier CTS tests.

Bug: 69407609
Bug: 63531115
Test: atest CtsWidgetTestCases:android.widget.cts.MagnifierTest
Change-Id: I49e53223730f5fbbf353f6574429c1b1a3d877a1