hg: jdk9/client/jdk: 7077826: Unset and empty DISPLAY variable is handled differently by JDK

[sergey.bylokhov at oracle.com]

Changeset: e0a52d4987aa
Author:    serb
Date:      2014-12-16 20:23 +0300
URL:       http://hg.openjdk.java.net/jdk9/client/jdk/rev/e0a52d4987aa

7077826: Unset and empty DISPLAY variable is handled differently by JDK
Reviewed-by: azvegint, ant

! src/java.desktop/share/classes/java/awt/GraphicsEnvironment.java
! test/java/awt/GraphicsEnvironment/TestDetectHeadless/TestDetectHeadless.sh
! test/java/awt/Toolkit/BadDisplayTest/BadDisplayTest.sh