Fix testMovingASlider on iPad

Change the auto-resizing mask on the "Other Text" text field.
With the previous mask, the test testMovingASlider would fail, as the "Slide"
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.