RFR 80044461: Cleanup new Boolean and single character strings

[roger riggs]

A quick sanity check please for these cleanup changes to remove uses of
new Boolean and using chars instead of single character strings contributed
by  Otávio Gonçalves de Santana.

These changes update multiple classes in the jdk9-dev repo (except 
client packages).

webrev: http://cr.openjdk.java.net/~rriggs/webrev-8044461-cleanup/
Issue: https://bugs.openjdk.java.net/browse/JDK-8044461

Thanks, Roger