[runtime] We don't need an actual instance type for JSIteratorResult.

src/objects-printer.cc

Index: src/objects-printer.cc
diff --git a/src/objects-printer.cc b/src/objects-printer.cc
index e3432a8da85aa324e836648338bffcbc2bfa594d..0534bcfdf9e974d9e68c70064e68c34f559a4494 100644
--- a/src/objects-printer.cc
+++ b/src/objects-printer.cc
@@ -146,9 +146,6 @@ void HeapObject::HeapObjectPrint(std::ostream& os) {  // NOLINT
     case JS_MAP_ITERATOR_TYPE:
       JSMapIterator::cast(this)->JSMapIteratorPrint(os);
       break;
-    case JS_ITERATOR_RESULT_TYPE:
-      JSIteratorResult::cast(this)->JSIteratorResultPrint(os);
-      break;
     case JS_WEAK_MAP_TYPE:
       JSWeakMap::cast(this)->JSWeakMapPrint(os);
       break;
@@ -800,14 +797,6 @@ void JSMapIterator::JSMapIteratorPrint(std::ostream& os) {  // NOLINT
 }
 
 
-void JSIteratorResult::JSIteratorResultPrint(std::ostream& os) {  // NOLINT
-  JSObjectPrintHeader(os, this, "JSIteratorResult");
-  os << "\n - done = " << Brief(done());
-  os << "\n - value = " << Brief(value());
-  os << "\n";
-}
-
-
 void JSWeakMap::JSWeakMapPrint(std::ostream& os) {  // NOLINT
   JSObjectPrintHeader(os, this, "JSWeakMap");
   os << "\n - table = " << Brief(table());