Prevent structuredClone transfer of immutable array buffers (which are not detachable)

Ref tc39/proposal-immutable-arraybuffer#30

Author: gibson042

source

@@ -3047,6 +3047,7 @@ a.setAttribute('href', 'https://example.com/'); // change the content attribute
      <li>The <dfn data-x-href="https://tc39.es/ecma262/#sec-isconstructor">IsConstructor</dfn> abstract operation</li>
      <li>The <dfn data-x-href="https://tc39.es/ecma262/#sec-isdatadescriptor">IsDataDescriptor</dfn> abstract operation</li>
      <li>The <dfn data-x-href="https://tc39.es/ecma262/#sec-isdetachedbuffer">IsDetachedBuffer</dfn> abstract operation</li>
+     <li>The <dfn data-x-href="https://tc39.es/ecma262/#sec-isimmutablebuffer">IsImmutableBuffer</dfn> abstract operation</li>
      <li>The <dfn data-x-href="https://tc39.es/ecma262/#sec-issharedarraybuffer">IsSharedArrayBuffer</dfn> abstract operation</li>
      <li>The <dfn data-x="js-NewObjectEnvironment" data-x-href="https://tc39.es/ecma262/#sec-newobjectenvironment">NewObjectEnvironment</dfn> abstract operation</li>
      <li>The <dfn data-x-href="https://tc39.es/ecma262/#sec-normalcompletion">NormalCompletion</dfn> abstract operation</li>
@@ -10463,7 +10464,8 @@ o.myself = o;</code></pre>
      <span>"<code>DataCloneError</code>"</span> <code>DOMException</code>.</p></li>
 
      <li><p>If <var>transferable</var> has an [[ArrayBufferData]] internal slot and
-     <span>IsSharedArrayBuffer</span>(<var>transferable</var>) is true, then throw a
+     <span>IsSharedArrayBuffer</span>(<var>transferable</var>) is true or
+     either <span>IsImmutableBuffer</span>(<var>transferable</var>) is true, then throw a
      <span>"<code>DataCloneError</code>"</span> <code>DOMException</code>.</p></li>
 
      <li><p>If <var>memory</var>[<var>transferable</var>] <span data-x="map exists">exists</span>,