WIP: Testing to see whether this fixes the yarn test issue.

Author: Marcelo Vanzin

pom.xml

@@ -1194,6 +1194,7 @@
                 launched by the tests have access to the correct test-time classpath.
               -->
               <SPARK_DIST_CLASSPATH>${test_classpath}</SPARK_DIST_CLASSPATH>
+              <JAVA_HOME>${java.home}</JAVA_HOME>
             </environmentVariables>
             <systemProperties>
               <java.awt.headless>true</java.awt.headless>
@@ -1224,6 +1225,7 @@
                 launched by the tests have access to the correct test-time classpath.
               -->
               <SPARK_DIST_CLASSPATH>${test_classpath}</SPARK_DIST_CLASSPATH>
+              <JAVA_HOME>${java.home}</JAVA_HOME>
             </environmentVariables>
             <systemProperties>
               <java.awt.headless>true</java.awt.headless>