No longer allow a policy exception just for workers

In particular, if you can execute script, you can execute a worker. Making workers an optional feature is not actually something user agents implement and has led to implementer confusion, e.g., web-platform-tests/wpt#41758.

source

@@ -115194,10 +115194,6 @@ enum <dfn enum>WorkerType</dfn> { "classic", "module" };
   steps:</p>
 
   <ol>
-   <li><p>The user agent may throw a <span>"<code>SecurityError</code>"</span>
-   <code>DOMException</code> if the request violates a policy decision (e.g. if the user agent is
-   configured to not allow the page to start dedicated workers).</p></li>
-
    <li><p>Let <var>outside settings</var> be the <span>current settings object</span>.</p>
 
    <li><p><span data-x="parse a url">Parse</span> the <var>scriptURL</var> argument relative to
@@ -115289,10 +115285,6 @@ interface <dfn interface>SharedWorker</dfn> : <span>EventTarget</span> {
   constructor is invoked:</p>
 
   <ol>
-   <li><p>Optionally, throw a <span>"<code>SecurityError</code>"</span> <code>DOMException</code>
-   if the request violates a policy decision (e.g. if the user agent is configured to not allow the
-   page to start shared workers).</p></li>
-
    <li><p>If <var>options</var> is a <code data-x="idl-DOMString">DOMString</code>, set
    <var>options</var> to a new <code>WorkerOptions</code> dictionary whose <code
    data-x="">name</code> member is set to the value of <var>options</var> and whose other members