Change auto-resizing mask on "Other Text" to avoid obscuring "Slide" on iPad

With the previous mask, the test testMovingASlider would fail, as the slider
was positioned behind this text field.
Fix testReturningFromATextField by waiting for keyboard to appear

On iPads, the keyboard takes a little time to appear, and pressing 'return'
before it has appeared doesn't do anything. Wait a little bit for the keyboard
to appear.