Allow compilation of classes in different ClassLoaders

Change-Id: Ib0420471590a4c6d16bc25285ef3876098eacb36
diff --git a/src/common_test.h b/src/common_test.h
index aa9229e..afe0c0f 100644
--- a/src/common_test.h
+++ b/src/common_test.h
@@ -148,7 +148,7 @@
     return DexFile::OpenZip(libcore_dex_file_name);
   }
 
-  PathClassLoader* AllocPathClassLoader(const DexFile* dex_file) {
+  const PathClassLoader* AllocPathClassLoader(const DexFile* dex_file) {
     CHECK(dex_file != NULL);
     class_linker_->RegisterDexFile(*dex_file);
     std::vector<const DexFile*> dex_files;