[modules] Basic support of exports

src/objects-debug.cc

Index: src/objects-debug.cc
diff --git a/src/objects-debug.cc b/src/objects-debug.cc
index 5a5888995533a64f6978831e431c7fc2cb668e58..b860e73d150b9ce06c62b7baf54f5936d5cb341c 100644
--- a/src/objects-debug.cc
+++ b/src/objects-debug.cc
@@ -166,6 +166,9 @@ void HeapObject::HeapObjectVerify() {
     case JS_PROXY_TYPE:
       JSProxy::cast(this)->JSProxyVerify();
       break;
+    case JS_MODULE_TYPE:
+      JSModule::cast(this)->JSModuleVerify();
+      break;
     case FOREIGN_TYPE:
       Foreign::cast(this)->ForeignVerify();
       break;
@@ -831,6 +834,7 @@ void JSRegExp::JSRegExpVerify() {
   }
 }
 
+void JSModule::JSModuleVerify() { CHECK(IsJSModule()); }
 
 void JSProxy::JSProxyVerify() {
   CHECK(IsJSProxy());