Prevent attachInternals() use before custom element constructor

Change to DOM: whatwg/dom#894.

Tests: web-platform-tests/wpt#25402.

source

@@ -66871,6 +66871,9 @@ customElements.define("x-foo", class extends HTMLElement {
       does.</p>
      </li>
 
+     <li><p>Set <var>element</var>'s <span>custom element state</span> to "<code
+     data-x="">precustomized</code>".</p></li>
+
      <li>
       <p>Let <var>constructResult</var> be the result of <span
       data-x="es-constructing-callback-functions">constructing</span> <var>C</var>, with no
@@ -66930,7 +66933,8 @@ customElements.define("x-foo", class extends HTMLElement {
     </ol>
 
     <p class="note">If the above steps threw an exception, then <var>element</var>'s <span>custom
-    element state</span> will remain "<code data-x="">failed</code>".</p>
+    element state</span> will remain "<code data-x="">failed</code>" or "<code
+    data-x="">precustomized</code>".</p>
    </li>
 
    <li>
@@ -67435,6 +67439,10 @@ dictionary <dfn>ValidityStateFlags</dfn> {
    <li><p>If <var>element</var>'s <span>attached internals</span> is true, then throw an
    <span>"<code>NotSupportedError</code>"</span> <code>DOMException</code>.</p></li>
 
+   <li><p>If <var>element</var>'s <span>custom element state</span> is not "<code
+   data-x="">precustomized</code>" or "<code data-x="">custom</code>", then throw a
+   <span>"<code>NotSupportedError</code>"</span> <code>DOMException</code>.</p></li>
+
    <li><p>Set <var>element</var>'s <span>attached internals</span> to true.</p></li>
 
    <li><p>Create a new <code>ElementInternals</code> instance