RFR [9] 8144995: Move sun.misc.HexDumpEncoder to sun.security.util

[Chris Hegarty]

sun.misc.HexDumpEncoder is an internal private API that is used almost
exclusively by the security library code. It should be moved out of sun.misc
and into a package more appropriate to its use, sun.security.util.

HexDumpEncoder extends CharacterEncoder, which is slated for later
removal, so the minimal implementation was copied in-place ( no new
code ).

http://cr.openjdk.java.net/~chegar/8144995/00/webrev/

-Chris.

[1] https://bugs.openjdk.java.net/browse/JDK-8144995