8u20 Request for approval for JDK-8039178

[Paul Govereau]

Please approve backport fix for bug 8039178  from jdk9 to jdk8u20. The 
patch is applied "as is" without any jdk8 specific changes.

Bug: https://bugs.openjdk.java.net/browse/JDK-8039178

JDK9 changesets:
   http://hg.openjdk.java.net/jdk9/jdk9/langtools/rev/008f76d3209a
   http://hg.openjdk.java.net/jdk9/jdk9/langtools/rev/b03893804cd3

Thanks,
Paul