hg: jdk/sandbox: 8204322: "+=" applied to String operands can provoke side effects

[chris.hegarty at oracle.com]

Changeset: 6659a8f57d78
Author:    vromero
Date:      2018-06-06 08:32 -0700
URL:       http://hg.openjdk.java.net/jdk/sandbox/rev/6659a8f57d78

8204322: "+=" applied to String operands can provoke side effects
Reviewed-by: mcimadamore, jlahoda, shade

! src/jdk.compiler/share/classes/com/sun/tools/javac/jvm/StringConcat.java
+ test/jdk/java/lang/String/concat/ImplicitStringConcatAssignLHS.java