Honor ANDROID_ROOT and ANDROID_DATA

Change-Id: I8e43093830a734694bbf7308d08dd18527302270
diff --git a/src/common_test.h b/src/common_test.h
index d55dfbd..4457cec 100644
--- a/src/common_test.h
+++ b/src/common_test.h
@@ -396,7 +396,7 @@
       CHECK(host_dir != NULL);
       return StringPrintf("%s/framework/core-hostdex.jar", host_dir);
     }
-    return std::string("/system/framework/core.jar");
+    return StringPrintf("%s/framework/core.jar", GetAndroidRoot());
   }
 
   const DexFile* OpenTestDexFile(const char* name) {