Reland^2 "[iterator-helpers] Unship due to incompat"

This is a reland of commit bab6798

Change since reland: A second breakage reported in chromium:1480783

Original change's description:
> Reland "[iterator-helpers] Unship due to incompat"
>
> This is a reland of commit 1a22cf9
>
> Change since revert: I mistakenly thought part of the finch
> kill-switch playbook is to keep it enabled on ToT. It's actually
> the opposite.
>
> Original change's description:
> > [iterator-helpers] Unship due to incompat
> >
> > Bug: chromium:1474613, v8:13558
> > Change-Id: Iccba26e5cd5dc1787172c78b6e4f6889ef67fcea
> > Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/4834350
> > Reviewed-by: Adam Klein <adamk@chromium.org>
> > Commit-Queue: Shu-yu Guo <syg@chromium.org>
> > Cr-Commit-Position: refs/heads/main@{#89741}
>
> Bug: chromium:1474613, v8:13558
> Change-Id: Idc421a114303f036622bff681c9fa252c9110b9d
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/4843761
> Commit-Queue: Rezvan Mahdavi Hezaveh <rezvan@chromium.org>
> Auto-Submit: Shu-yu Guo <syg@chromium.org>
> Commit-Queue: Shu-yu Guo <syg@chromium.org>
> Reviewed-by: Rezvan Mahdavi Hezaveh <rezvan@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#89800}

Bug: chromium:1474613, v8:13558
Change-Id: Ia933c874508f1ec10ea4718c6378858cd5bec8f9
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/4854732
Reviewed-by: Rezvan Mahdavi Hezaveh <rezvan@chromium.org>
Auto-Submit: Shu-yu Guo <syg@chromium.org>
Commit-Queue: Rezvan Mahdavi Hezaveh <rezvan@chromium.org>
Cr-Commit-Position: refs/heads/main@{#89905}

src/flags/flag-definitions.h

@@ -278,7 +278,8 @@ DEFINE_BOOL(js_shipping, true, "enable all shipped JavaScript features")
 
 // Features that are complete (but still behind the --harmony flag).
 #define HARMONY_STAGED_BASE(V)                  \
-  V(harmony_set_methods, "harmony Set Methods")
+  V(harmony_set_methods, "harmony Set Methods") \
+  V(harmony_iterator_helpers, "JavaScript iterator helpers")
 
 #define JAVASCRIPT_STAGED_FEATURES_BASE(V) \
   V(js_promise_withresolvers, "Promise.withResolvers")
@@ -303,8 +304,7 @@ DEFINE_WEAK_IMPLICATION(harmony_rab_gsab_transfer, harmony_rab_gsab)
   V(harmony_regexp_unicode_sets, "harmony RegExp Unicode Sets")        \
   V(harmony_json_parse_with_source, "harmony json parse with source")  \
   V(harmony_rab_gsab_transfer, "harmony ArrayBuffer.transfer")         \
-  V(harmony_array_grouping, "harmony array grouping")                  \
-  V(harmony_iterator_helpers, "JavaScript iterator helpers")
+  V(harmony_array_grouping, "harmony array grouping")
 
 #define JAVASCRIPT_SHIPPING_FEATURES_BASE(V)
 

test/mjsunit/es6/iterator-prototype.js

@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+// Flags: --harmony-iterator-helpers
+
 var arrayIteratorPrototype = [].entries().__proto__;
 var iteratorPrototype = arrayIteratorPrototype.__proto__;
 

test/mozilla/mozilla.status

@@ -546,6 +546,7 @@
 
   # Uses Mozilla-specific QName, XML, XMLList and Iterator.
   'js1_5/Regress/regress-407323': [FAIL_OK],
+  'js1_5/Regress/regress-407957': [FAIL_OK],
 
 
   # Relies on JavaScript 1.2 / 1.3 deprecated features.