Restore original scroll position on =

Bug: 22041219

Restore default scrolling position when hitting enter after scrolling
an instant display result.

We could instead preserve the position and fix the display logic to
no longer get confused by a non-default initial position.  But this
feels more natural to me.

Change-Id: I43bb936b5bb1b5af7a7befb90fdfc0f745fb7729