hg: jdk9/sandbox/jdk: JDK-8054307-branch: AbstractStringBuilder cleanup and bug fix

[xueming.shen at oracle.com]

Changeset: 9e7139d48837
Author:    sherman
Date:      2015-10-23 00:17 -0700
URL:       http://hg.openjdk.java.net/jdk9/sandbox/jdk/rev/9e7139d48837

JDK-8054307-branch: AbstractStringBuilder cleanup and bug fix

! src/java.base/share/classes/java/lang/AbstractStringBuilder.java
! test/java/lang/StringBuffer/Exceptions.java
! test/java/lang/StringBuilder/Exceptions.java