[flexiglass] Converts tests to deviceless.

All unit and integration tests are converted into shared tests so they
can run with or without a device.

PinInputViewModel needed some internal things to be made public so the
test module can see them.

SceneContainterFlagsTest was left unconverted because it's a
non-screenshot parameterized test, which is not yet supported.

Fix: 302542615
Test: N/A these are tests
Change-Id: I709ccbe91293fbcaae3bc84250f4c987e92d7730