RFR [9]: Remove character coders from sun.misc

[Chris Hegarty]

As part of the preparation for JEP 260 [1], and the cleanup of technical debt in
sun.misc, I am proposing to remove the character coders.

Base abstract classes for the coders.
  $ hg rm src/java.base/share/classes/sun/misc/CharacterEncoder.java 
  $ hg rm src/java.base/share/classes/sun/misc/CharacterDecoder.java

Base64, replaced with standard API in Java SE 8 [2]. 
  $ hg rm src/java.base/share/classes/sun/misc/BASE64Decoder.java
  $ hg rm src/java.base/share/classes/sun/misc/BASE64Encoder.java

Uuencoding [3], most recently seen in use back in 2006 in ant 1.6.5, before
being replaced in 1.7.0 with their own copy.
  $ hg rm src/java.base/share/classes/sun/misc/UUDecoder.java
  $ hg rm src/java.base/share/classes/sun/misc/UUEncoder.java

Lesser known coders designed to convert binary data into printable characters.
The characters are assumed to exist, but they are not assumed to be ASCII.
No sightings in the wild!
  $ hg rm src/java.base/share/classes/sun/misc/UCDecoder.java 
  $ hg rm src/java.base/share/classes/sun/misc/UCEncoder.java

Related tests:
  $ hg rm test/sun/misc/Encode/
  removing test/sun/misc/Encode/DecodeBuffer.java 
  removing test/sun/misc/Encode/Encode.java
  removing test/sun/misc/Encode/GetBytes.java

-Chris.

[1] https://bugs.openjdk.java.net/browse/JDK-8132928
[2] http://docs.oracle.com/javase/8/docs/api/java/util/Base64.html
[3] https://en.wikipedia.org/wiki/Uuencoding