Rip out most of our outdated modules implementation.

src/contexts-inl.h

Index: src/contexts-inl.h
diff --git a/src/contexts-inl.h b/src/contexts-inl.h
index 990b50e1af40a2663af42ce2571b931c7c56cbb1..ce2c97be753f774d04bfa22cbd47707d6ded1b60 100644
--- a/src/contexts-inl.h
+++ b/src/contexts-inl.h
@@ -67,10 +67,6 @@ void Context::set_extension(HeapObject* object) {
 }
 
 
-JSModule* Context::module() { return JSModule::cast(get(EXTENSION_INDEX)); }
-void Context::set_module(JSModule* module) { set(EXTENSION_INDEX, module); }
-
-
 Context* Context::native_context() {
   Object* result = get(NATIVE_CONTEXT_INDEX);
   DCHECK(IsBootstrappingOrNativeContext(this->GetIsolate(), result));