RFR [9] 8149122: Move sun.misc.URLClassPath and Resource to an internal package

[Chris Hegarty]

sun.misc.URLClassPath, and its accompanying Resource, are not
"Critical APIs", as defined by JEP 260, so they should be moved
out of sun.misc and placed into a more appropriate package where
they can be encapsulated.

http://cr.openjdk.java.net/~chegar/8149122/
https://bugs.openjdk.java.net/browse/JDK-8149122

-Chris.