Revert to previous text selection behavior

There was a new behavior that starting "Select text" would allow you to
swipe from beginning to end and immediately copy that. This change
reverts to the previous behavior that "Select text" will start where
your cursor is currently and any tap will extend the selection from that
origin to the point of the tap.

Change-Id: Ib955cc8d62a652f518435953da2f54e810d9dfb0