Fix bad assert in HostResolveImportedModule

For cyclic module graphs, this assert is overzealous; this adjusts it
to assert only what we need. Closes whatwg#2596.

source

@@ -88510,9 +88510,7 @@ import "https://example.com/foo/../module2.js";</pre>
    data-x="concept-module-script-instantiation-error">instantiation error</span>.</p></li>
 
    <li><p>Assert: <var>resolved module script</var>'s <span
-   data-x="concept-module-script-instantiation-state">instantiation state</span> is "<code
-   data-x="">instantiated</code>" (and thus its <span
-   data-x="concept-module-script-module-record">module record</span> is not null).</p></li>
+   data-x="concept-module-script-module-record">module record</span> is not null.</p></li>
 
    <li><p>Return <var>resolved module script</var>'s <span
    data-x="concept-module-script-module-record">module record</span>.</p></li>