Do not fire error events on inactive globals

That is, on globals whose responsible document is not fully active.
Discussed in #1956.

source

@@ -87431,15 +87431,20 @@ document.querySelector("button").addEventListener("click", bound);
 
   <p>When the user agent is required to <dfn data-x="report the error">report an error</dfn> for a
   particular <span data-x="concept-script">script</span> <var>script</var> with a particular
-  position <var>line</var>:<var>col</var>, using a particular target <var>target</var>, it must run these steps, after which the error is either <dfn
-  data-x="concept-error-handled"><i>handled</i></dfn> or <dfn data-x="concept-error-nothandled"><i>not
-  handled</i></dfn>:</p>
+  position <var>line</var>:<var>col</var>, using a particular target <span>global object</span>
+  <var>target</var>, it must run these steps, after which the error is either <dfn
+  data-x="concept-error-handled"><i>handled</i></dfn> or <dfn
+  data-x="concept-error-nothandled"><i>not handled</i></dfn>:</p>
 
   <ol>
 
    <li><p>If <var>target</var> is <span>in error reporting mode</span>, then abort these
    steps; the error is <i data-x="concept-error-nothandled">not handled</i>.</p></li>
 
+   <li><p>If <var>target</var>'s <span>responsible <code>Document</code></span> is not <span>fully
+   active</span>, then abort these steps; the error is <i data-x="concept-error-nothandled">not
+   handled</i>.</p></li>
+
    <li><p>Let <var>target</var> be <dfn>in error reporting mode</dfn>.</p></li>
 
    <li><p>Let <var>message</var> be a user-agent-defined string describing the error in a