Render to measured size when using expand mode

When using RenderingMode.V_SCROLL or RenderingMode.H_SCROLL, if the
screen size is smaller than the measured size but as large as the
desired size, the layout will render incorrectly and won't expand.
This changes that to expand to at least the size of the screen.

Added tests for the V_SCROLL and H_SCROLL modes.

Bug: http://b.android.com/174928
Change-Id: I22686903560775e2e4f362af1d7b50c9b985467d