Perform manual iteration in AddValueToKeyedGroup

Re: #19 (comment)

index.html

@@ -2414,7 +2414,7 @@ <h1><span class="secnum">2.2</span> Array.prototype.groupByMap ( <var>callbackfn
   <emu-clause id="sec-add-value-to-keyed-group" type="abstract operation" aoid="AddValueToKeyedGroup">
     <h1><span class="secnum">2.3</span> AddValueToKeyedGroup ( <var>groups</var>, <var>key</var>, <var>value</var> )</h1>
     <p>The abstract operation AddValueToKeyedGroup takes arguments <var>groups</var> (a <emu-xref href="#sec-list-and-record-specification-type"><a href="https://tc39.es/ecma262/#sec-list-and-record-specification-type">List</a></emu-xref> of Records that have [[Key]] and [[Elements]] fields), <var>key</var> (an <emu-xref href="#sec-ecmascript-language-types"><a href="https://tc39.es/ecma262/#sec-ecmascript-language-types">ECMAScript language value</a></emu-xref>), and <var>value</var> (an <emu-xref href="#sec-ecmascript-language-types"><a href="https://tc39.es/ecma262/#sec-ecmascript-language-types">ECMAScript language value</a></emu-xref>). It performs the following steps when called:</p>
-    <emu-alg><ol><li>If <var>groups</var> contains a <emu-xref href="#sec-list-and-record-specification-type"><a href="https://tc39.es/ecma262/#sec-list-and-record-specification-type">Record</a></emu-xref> <var>g</var> such that !&nbsp;<emu-xref aoid="SameValue" id="_ref_19"><a href="https://tc39.es/ecma262/#sec-samevalue">SameValue</a></emu-xref>(<var>g</var>.[[Key]], <var>key</var>) is <emu-val>true</emu-val>, then<ol><li><emu-xref href="#assert"><a href="https://tc39.es/ecma262/#assert">Assert</a></emu-xref>: exactly one element of <var>groups</var> meets this criteria.</li><li>Append <var>value</var> as the last element of <var>g</var>.[[Elements]].</li></ol></li><li>Else,<ol><li>Let <var>group</var> be the <emu-xref href="#sec-list-and-record-specification-type"><a href="https://tc39.es/ecma262/#sec-list-and-record-specification-type">Record</a></emu-xref> { [[Key]]: <var>key</var>, [[Elements]]: « <var>value</var> » }.</li><li>Append <var>group</var> as the last element of <var>groups</var>.</li></ol></li></ol></emu-alg>
+    <emu-alg><ol><li>For each <emu-xref href="#sec-list-and-record-specification-type"><a href="https://tc39.es/ecma262/#sec-list-and-record-specification-type">Record</a></emu-xref> { [[Key]], [[Elements]] } <var>g</var> of <var>groups</var>, do<ol><li>If !&nbsp;<emu-xref aoid="SameValue" id="_ref_19"><a href="https://tc39.es/ecma262/#sec-samevalue">SameValue</a></emu-xref>(<var>g</var>.[[Key]], <var>key</var>) is <emu-val>true</emu-val>, then<ol><li><emu-xref href="#assert"><a href="https://tc39.es/ecma262/#assert">Assert</a></emu-xref>: exactly one element of <var>groups</var> meets this criteria.</li><li>Append <var>value</var> as the last element of <var>g</var>.[[Elements]].</li><li>Return.</li></ol></li></ol></li><li>Let <var>group</var> be the <emu-xref href="#sec-list-and-record-specification-type"><a href="https://tc39.es/ecma262/#sec-list-and-record-specification-type">Record</a></emu-xref> { [[Key]]: <var>key</var>, [[Elements]]: « <var>value</var> » }.</li><li>Append <var>group</var> as the last element of <var>groups</var>.</li></ol></emu-alg>
   </emu-clause>
   </ins>
 </emu-clause><emu-annex id="sec-copyright-and-software-license">

spec.emu

@@ -105,12 +105,13 @@ location: https://tc39.es/proposal-array-grouping/
     <dl class="header">
     </dl>
     <emu-alg>
-        1. If _groups_ contains a Record _g_ such that ! SameValue(_g_.[[Key]], _key_) is *true*, then
-          1. Assert: exactly one element of _groups_ meets this criteria.
-          1. Append _value_ as the last element of _g_.[[Elements]].
-        1. Else,
-          1. Let _group_ be the Record { [[Key]]: _key_, [[Elements]]: &laquo; _value_ &raquo; }.
-          1. Append _group_ as the last element of _groups_.
+        1. For each Record { [[Key]], [[Elements]] } _g_ of _groups_, do
+          1. If ! SameValue(_g_.[[Key]], _key_) is *true*, then
+            1. Assert: exactly one element of _groups_ meets this criteria.
+            1. Append _value_ as the last element of _g_.[[Elements]].
+            1. Return.
+        1. Let _group_ be the Record { [[Key]]: _key_, [[Elements]]: &laquo; _value_ &raquo; }.
+        1. Append _group_ as the last element of _groups_.
     </emu-alg>
   </emu-clause>
   </ins>