Syncing percent test setup with other parts of support library.

* Use JUnit4 annotations for various methods
* Use common base activity / test class (this is preparation for
tests for PercentRelativeLayout class)
* Account for floating point arithmetic in fuzzy assertions
* Use Espresso actions for running code that affects the visual
state of components (when we change the layout direction for RTL
aware attributes)

Change-Id: Icc5d39d24b4eb02e63f52ded0ef8ab526219325a
8 files changed