Review #241961 - Run in Felix fails

Please review the bug fix for

https://netbeans.org/bugzilla/show_bug.cgi?id=241961

Description: When running NetBeans platform application in Felix, 
IllegalArgumentException occurred. Problem is with libs.javafx module. 
When iterating over classpath items defined in manifest of that module, 
there should be dynamically checked location of jfxrt.jar jvm library, 
which is different for jre7 and jre8. The fix is solving this problem by 
searching for appropriate library.

Impact: Run in Felix

http://hg.netbeans.org/main-silver/rev/e45908f3e6f8


Thanks,
Martin