Don't pause overflowchanged events after React editor updates

Fixes #2237

Previously, operations such as typing and scrolling were triggering
overflowchanged events on the editor, which concerned me because we
were performing lots of unnecessary measurements of the scroll view.
Now that we draw extra lines above and below the visible screen row
range, this doesn't happen, so we can remove this pausing code which
was delaying the resizing of the editor in certain situations.