8267954: Shared classes that failed to load should not be loaded again

Reviewed-by: iklam, ccheung

src/hotspot/share/oops/instanceKlass.cpp

@@ -2496,6 +2496,7 @@ void InstanceKlass::restore_unshareable_info(ClassLoaderData* loader_data, Handl
   // before the InstanceKlass is added to the SystemDictionary. Make
   // sure the current state is <loaded.
   assert(!is_loaded(), "invalid init state");
+  assert(!shared_loading_failed(), "Must not try to load failed class again");
   set_package(loader_data, pkg_entry, CHECK);
   Klass::restore_unshareable_info(loader_data, protection_domain, CHECK);