Install iterator meta objects via utils object.

src/js/prologue.js

Index: src/js/prologue.js
diff --git a/src/js/prologue.js b/src/js/prologue.js
index e169018910bffe45d994d41095220983f718eebd..0b94e2b6544e5ad9ae593302178f9be9d39e9172 100644
--- a/src/js/prologue.js
+++ b/src/js/prologue.js
@@ -182,6 +182,7 @@ function PostNatives(utils) {
     "InnerArrayToLocaleString",
     "IsNaN",
     "MapEntries",
+    "MapIterator",
     "MapIteratorNext",
     "MathMax",
     "MathMin",
@@ -190,6 +191,8 @@ function PostNatives(utils) {
     "ObserveArrayMethods",
     "ObserveObjectMethods",
     "OwnPropertyKeys",
+    "SameValueZero",
+    "SetIterator",
     "SetIteratorNext",
     "SetValues",
     "SymbolToString",
@@ -230,12 +233,9 @@ function PostExperimentals(utils) {
     imports_from_experimental(exports_container);
   }
 
-  exports_container = UNDEFINED;
-
-  utils.PostExperimentals = UNDEFINED;
-  utils.PostDebug = UNDEFINED;
-  utils.Import = UNDEFINED;
   utils.Export = UNDEFINED;
+  utils.PostDebug = UNDEFINED;
+  utils.PostExperimentals = UNDEFINED;
 }
 
 
@@ -246,12 +246,14 @@ function PostDebug(utils) {
 
   exports_container = UNDEFINED;
 
+  utils.Export = UNDEFINED;
+  utils.Import = UNDEFINED;
+  utils.ImportNow = UNDEFINED;
   utils.PostDebug = UNDEFINED;
   utils.PostExperimentals = UNDEFINED;
-  utils.Import = UNDEFINED;
-  utils.Export = UNDEFINED;
 }
 
+
 // -----------------------------------------------------------------------
 
 %OptimizeObjectForAddingMultipleProperties(utils, 13);