8178604: JVM does not allow defining boot loader modules in exploded build after module system initialization Summary: Allow defining of boot loader modules after initialization but add locks to synchronize access to exploded build list Reviewed-by: dholmes, lfoltan

^build/
^dist/
^.idea/
nbproject/private/
^webrev
^.src-rev$
^.jib/
.DS_Store
.metadata/
.recommenders/