Make art use core-libart explicitly

Change-Id: Ibc75910df56428dd8d5d2a4bab41dc3d2a3c61d7
diff --git a/src/common_test.h b/src/common_test.h
index 3baa77c..8d8ad5e 100644
--- a/src/common_test.h
+++ b/src/common_test.h
@@ -396,7 +396,7 @@
   }
 
   std::string GetLibCoreDexFileName() {
-    return GetDexFileName("core");
+    return GetDexFileName("core-libart");
   }
 
   std::string GetConscryptFileName() {