hg: openjfx/9-dev/rt: Revert fix for 8134923 due to regression caught during sanity testing

[kevin.rushforth at oracle.com]

Changeset: f1b349874ef0
Author:    kcr
Date:      2015-11-16 12:27 -0800
URL:       http://hg.openjdk.java.net/openjfx/9-dev/rt/rev/f1b349874ef0

Revert fix for 8134923 due to regression caught during sanity testing
Backed out changeset 9cefb201457c

! modules/controls/src/main/java/javafx/scene/control/MultipleSelectionModelBase.java