sun.misc.MessageUtils provides low-level access for writing “error” messages
to stdout and stderr. It is, effectively, used in just one place in the JDK, String
coding, when the specific encoding is not available. Since this is the only usage,
the minimal functionality required by String coding can be moved to StringCoding,
and MessageUtils removed.

Note: there are a couple of unused reference to MessageUtils in the desktop
module and a build tool that need to be cleaned up.