[modules] Don't unnecessarily keep function alive after evaluation.

src/api.cc

Index: src/api.cc
diff --git a/src/api.cc b/src/api.cc
index adb62f54fca0b1c5195e54ef2e7868226e2d5061..0726d2ff7d657f077b9d16762087e93fe2e29cc3 100644
--- a/src/api.cc
+++ b/src/api.cc
@@ -1930,7 +1930,7 @@ MaybeLocal<Value> Module::Evaluate(Local<Context> context) {
 
   i::Handle<i::Module> self = Utils::OpenHandle(this);
   // It's an API error to call Evaluate before Instantiate.
-  CHECK(self->code()->IsJSFunction());
+  CHECK(self->instantiated());
 
   Local<Value> result;
   has_pending_exception = !ToLocal(i::Module::Evaluate(self), &result);