[8u] review request: RT-36232: [Quantum] SecurityException on exit when running any FX program with security manager

[Kevin Rushforth]

Felipe or Anthony,

Please review the following fix for a regression introduced in 8u20 that 
causes untrusted applications to get an exception on exit.

JIRA:  https://javafx-jira.kenai.com/browse/RT-36232
Webrev:  http://cr.openjdk.java.net/~kcr/RT-36232/

Thanks.

-- Kevin