hg: jdk9/hs-rt/hotspot: 8149837: String.intern creates morre work than necessary for G1

[kim.barrett at oracle.com]

Changeset: 8c94907406e1
Author:    drwhite
Date:      2016-02-17 18:02 -0500
URL:       http://hg.openjdk.java.net/jdk9/hs-rt/hotspot/rev/8c94907406e1

8149837: String.intern creates morre work than necessary for G1
Summary: Only use the SATB read barrier when reading existing strings from string table, not when adding new strings.
Reviewed-by: stefank, kbarrett

! src/share/vm/classfile/stringTable.cpp