Skip a test intentionally; Maven already does the same

Big thanks to Julian for showing me where this exclusion logic lives
in the Maven configuration.  There's a "**/*AndroidLibs*.java"
exclusion pattern in the top-level "pom.xml".

com.ibm.wala.dalvik.test/build.gradle

@@ -141,6 +141,6 @@ processTestResources {
 test {
 	maxHeapSize = '800M'
 
-	// https://github.com/liblit/WALA/issues/5
+	// intentionally skipped; not a bug
 	exclude '**/DynamicDalvikComparisonTestForAndroidLibs.class'
 }