Exception thrown in custom preloader should not make app fail to load

Steps to reproduce
Launch the following applet
http://rehte.cn.oracle.com:8080/wshost/new_ws/deployment/src/javafx/fxfeaturesTest/fxfeaturesTest/html/ExceptionPreloader.html (A runtime exception is thrown in preloader)
or
http://rehte.cn.oracle.com:8080/wshost/new_ws/deployment/src/javafx/fxfeaturesTest/fxfeaturesTest/html/CallNonExistJSPreloader.html(call a non-exist js in preloader,JSException is thrown in preloader)
If the applets can not be launched, bug is reproduced.

Source code location:
http://rehte.cn.oracle.com:8080/wshost/new_ws/deployment/src/javafx/fxfeaturesTest/fxfeaturesTest/src