Fix for gtest missing core classes, attempt 2

common_runtime_test loads both core-libart and
core-oj

Change-Id: I8a4d5750b99aed2e500cad89b841a57fe9c1ca69
diff --git a/runtime/zip_archive_test.cc b/runtime/zip_archive_test.cc
index 70a4dda..ced47e3 100644
--- a/runtime/zip_archive_test.cc
+++ b/runtime/zip_archive_test.cc
@@ -32,7 +32,7 @@
 
 TEST_F(ZipArchiveTest, FindAndExtract) {
   std::string error_msg;
-  std::unique_ptr<ZipArchive> zip_archive(ZipArchive::Open(GetLibCoreDexFileName().c_str(), &error_msg));
+  std::unique_ptr<ZipArchive> zip_archive(ZipArchive::Open(GetLibCoreDexFileNames()[0].c_str(), &error_msg));
   ASSERT_TRUE(zip_archive.get() != nullptr) << error_msg;
   ASSERT_TRUE(error_msg.empty());
   std::unique_ptr<ZipEntry> zip_entry(zip_archive->Find("classes.dex", &error_msg));