RFR 8141285: NameCode should pass tests from BytecodeNameTest.java

[Sundararajan Athijegannathan]

Please review http://cr.openjdk.java.net/~sundar/8141285/webrev.00/ for 
https://bugs.openjdk.java.net/browse/JDK-8141285

NameCodec has similar functionality (with a minor bug in '\' handling) 
as in sun.invoke.util.BytecodeName.java (which seems to be old code, but 
unused in jdk repo!). Using code in BytecodeName.java in NameCodec.java 
now - only minimal subset needed for decode, encode. Also, adding tests 
for NameCodec.java derived from (older) mlvm test BytecodeNameTest.java

Thanks,
-Sundar