Editorial: %AsyncIterator.prototype% -> %AsyncIteratorPrototype%

Commit f1b22ef (tc39#1376) changed 2 occurrences of
  "%AsyncIteratorPrototype%
to
  "%AsyncIterator.prototype%
but the latter assumes a well-known intrinsic named "%AsyncIterator%",
which doesn't exist.

This commit changes them back.

spec.html

@@ -37092,7 +37092,7 @@ <h1>The %AsyncFromSyncIteratorPrototype% Object</h1>
         <ul>
           <li>has properties that are inherited by all Async-from-Sync Iterator Objects.</li>
           <li>is an ordinary object.</li>
-          <li>has a [[Prototype]] internal slot whose value is %AsyncIterator.prototype%.</li>
+          <li>has a [[Prototype]] internal slot whose value is %AsyncIteratorPrototype%.</li>
           <li>has the following properties:</li>
         </ul>
 
@@ -37656,7 +37656,7 @@ <h1>Properties of the AsyncGenerator Prototype Object</h1>
         <li>is the initial value of the `prototype` property of %AsyncGenerator% (the AsyncGeneratorFunction.prototype).</li>
         <li>is an ordinary object.</li>
         <li>is not an AsyncGenerator instance and does not have an [[AsyncGeneratorState]] internal slot.</li>
-        <li>has a [[Prototype]] internal slot whose value is %AsyncIterator.prototype%.</li>
+        <li>has a [[Prototype]] internal slot whose value is %AsyncIteratorPrototype%.</li>
         <li>has properties that are indirectly inherited by all AsyncGenerator instances.</li>
       </ul>