Bug 1654235 - Make sure Private Fields TypedObject test only runs when TypedObjects are available r=jorendorff

As well, following the footsteps of our other tests, require the shell.

Differential Revision: https://phabricator.services.mozilla.com/D84344

js/src/tests/non262/PrivateName/typedObject.js

@@ -1,4 +1,4 @@
-// |reftest| shell-option(--enable-private-fields)
+// |reftest| shell-option(--enable-private-fields) skip-if(!this.hasOwnProperty("TypedObject")||!xulRuntime.shell) -- requires typed objects and the shell option
 
 class Base {
   constructor(o) {