FormLineEdit: Don't run focusout/formatfield actions when losing focus because of window management

Adobe Reader doesn't do it and if we do it can end up crashing because
we end up running two focusout actions in parallel and our script system
is not prepared for that:

Scenario:
 * Tab out of a field
 * Script for that focusout runs
 * focus goes to next field
 * script for that focusout shows an alert()
 * second focusout script for that field runs while the first is running
 * bad stuff

BUGS: 435833