Using integrity with "no-cors" is fine same-origin

This exception also broke simple service worker passthrough handling.

Tests: see https://bugzilla.mozilla.org/show_bug.cgi?id=1393439.

Fixes whatwg#583.

fetch.bs

@@ -4959,9 +4959,6 @@ constructor must run these steps:
    <li><p>If <var>r</var>'s <a for=Request>request</a>'s <a for=request>method</a> is not a
    <a>CORS-safelisted method</a>, then <a>throw</a> a <code>TypeError</code>.
 
-   <li><p>If <var>request</var>'s <a for=request>integrity metadata</a> is not the empty string,
-   then <a>throw</a> a <code>TypeError</code>.
-
    <li><p>Set <var>r</var>'s <a for=Request>headers</a>'s <a for=Headers>guard</a> to
    "<code>request-no-cors</code>".
   </ol>