JRE-394 backport: JDK-8173654: Regression since 8u60: System.getenv doesn't return env var set in JNI code

Added property to enable unit tests jni code compilation
diff --git a/idea/java/build.gradle b/idea/java/build.gradle
index 701a04b..73a8ce3 100644
--- a/idea/java/build.gradle
+++ b/idea/java/build.gradle
@@ -139,7 +139,9 @@
     }
 }
 
-test.dependsOn  'envSharedLibrary'
+if (project.hasProperty('jnitests')) {
+    test.dependsOn 'envSharedLibrary'
+}
 
 tasks.compileJava.enabled = false
 tasks.compileTestJava.dependsOn.clear()