Improve shared element tests and test framework

It is cumbersome to manually input all interpolated values for each
frame. It's also hard to change tests or create variations because
changing a value requires to change all interpolated values.

Test: TEST_ONLY
Bug: b/376659778
Flag: com.android.systemui.scene_container
Change-Id: I4818f389554feb60335cffa2222cb1ca834dd102