Remove notest about executing scripts that have moved documents

This remove notes pointing to whatwg#2137, and thus closes whatwg#2137. We'll proceed with
preventing scripts from executing if they've moved between documents, as this is
now shipping in two engines.

source

@@ -57582,13 +57582,8 @@ o............A....e
    <li><p>Set the element's <span>preparation-time document</span> to its <span>node
    document</span>.</p>
 
-   <li>
-    <p>If <var>parser document</var> is non-null, and <var>parser document</var> is not equal to
-    the element's <span>preparation-time document</span>, then return.</p>
-
-    <p class="XXX">This step is not interoperable and is under debate: see <a
-    href="https://github.com/whatwg/html/issues/2137">issue #2137</a>.</p>
-   </li>
+   <li><p>If <var>parser document</var> is non-null, and <var>parser document</var> is not equal to
+   the element's <span>preparation-time document</span>, then return.</p></li>
 
    <li id="script-processing-noscript">
 
@@ -57946,15 +57941,6 @@ o............A....e
   <ol>
    <li><p>Let <var>document</var> be <var>scriptElement</var>'s <span>node document</span>.</p></li>
 
-   <li>
-    <p>If <var>scriptElement</var>'s <span>parser document</span> is non-null, and
-    <var>scriptElement</var>'s <span>parser document</span> is not equal to <var>document</var>,
-    then return.</p>
-
-    <p class="XXX">This step is not interoperable and is under debate: see <a
-    href="https://github.com/whatwg/html/issues/2137">issue #2137</a>.</p>
-   </li>
-
    <li><p>If <var>scriptElement</var>'s <span>preparation-time document</span> is not equal to
    <var>document</var>, then return.</p></li>