Do not close when iterator has already been requested closed

spec.html

@@ -42957,7 +42957,7 @@ <h1>%AsyncFromSyncIteratorPrototype%.next ( [ _value_ ] )</h1>
             1. Else,
               1. Let _result_ be IteratorNext(_syncIteratorRecord_).
             1. IfAbruptRejectPromise(_result_, _promiseCapability_).
-            1. Return ! AsyncFromSyncIteratorContinuation(_result_, _promiseCapability_, _syncIteratorRecord_).
+            1. Return ! AsyncFromSyncIteratorContinuation(_result_, _promiseCapability_, _syncIteratorRecord_, *true*).
           </emu-alg>
         </emu-clause>
 
@@ -42983,7 +42983,7 @@ <h1>%AsyncFromSyncIteratorPrototype%.return ( [ _value_ ] )</h1>
             1. If Type(_result_) is not Object, then
               1. Perform ! Call(_promiseCapability_.[[Reject]], *undefined*, &laquo; a newly created *TypeError* object &raquo;).
               1. Return _promiseCapability_.[[Promise]].
-            1. Return ! AsyncFromSyncIteratorContinuation(_result_, _promiseCapability_, _syncIteratorRecord_).
+            1. Return ! AsyncFromSyncIteratorContinuation(_result_, _promiseCapability_, _syncIteratorRecord_, *false*).
           </emu-alg>
         </emu-clause>
 
@@ -43009,7 +43009,7 @@ <h1>%AsyncFromSyncIteratorPrototype%.throw ( [ _value_ ] )</h1>
             1. If Type(_result_) is not Object, then
               1. Perform ! Call(_promiseCapability_.[[Reject]], *undefined*, &laquo; a newly created *TypeError* object &raquo;).
               1. Return _promiseCapability_.[[Promise]].
-            1. Return ! AsyncFromSyncIteratorContinuation(_result_, _promiseCapability_, _syncIteratorRecord_).
+            1. Return ! AsyncFromSyncIteratorContinuation(_result_, _promiseCapability_, _syncIteratorRecord_, *true*).
           </emu-alg>
         </emu-clause>
       </emu-clause>
@@ -43044,9 +43044,10 @@ <h1>Properties of Async-from-Sync Iterator Instances</h1>
       <emu-clause id="sec-asyncfromsynciteratorcontinuation" type="abstract operation" oldids="sec-async-from-sync-iterator-value-unwrap-functions">
         <h1>
           AsyncFromSyncIteratorContinuation (
-            _result_: unknown,
-            _promiseCapability_: a PromiseCapability Record,
-            _syncIteratorRecord_: unknown,
+          _result_: unknown,
+          _promiseCapability_: a PromiseCapability Record,
+          _syncIteratorRecord_: unknown,
+          _closeOnRejection_: a Boolean,
           )
         </h1>
         <dl class="header">
@@ -43058,14 +43059,14 @@ <h1>
           1. Let _value_ be IteratorValue(_result_).
           1. IfAbruptRejectPromise(_value_, _promiseCapability_).
           1. Let _valueWrapper_ be PromiseResolve(%Promise%, _value_).
-          1. If _valueWrapper_ is an abrupt completion, and _done_ is not *true*, then
+          1. If _valueWrapper_ is an abrupt completion, _done_ is *false*, and _closeOnRejection_ is *true*, then
             1. Set _valueWrapper_ to IteratorClose(_syncIteratorRecord_, _valueWrapper_).
           1. IfAbruptRejectPromise(_valueWrapper_, _promiseCapability_).
           1. Let _unwrap_ be a new Abstract Closure with parameters (_value_) that captures _done_ and performs the following steps when called:
             1. Return ! CreateIterResultObject(_value_, _done_).
           1. Let _onFulfilled_ be ! CreateBuiltinFunction(_unwrap_, 1, *""*, &laquo; &raquo;).
           1. NOTE: _onFulfilled_ is used when processing the *"value"* property of an IteratorResult object in order to wait for its value if it is a promise and re-package the result in a new "unwrapped" IteratorResult object.
-          1. If _done_ is *true*, then
+          1. If _done_ is *true*, or if _closeOnRejection_ is *false*, then
             1. Let _onRejected_ be *undefined*.
           1. Else,
             1. Let _closeIterator_ be a new Abstract Closure with parameters (_error_) that captures _syncIteratorRecord_ and performs the following steps when called: