Bug 1781332 - Disable iframe accessKey tests. r=Jamie

There is a bug in DOM (bug 1796846) that prematurely registers
access keys before there is a presShell in iframes.

We will get better coverage for our module if we disable the
iframe tests and enable it on mac.

Differential Revision: https://phabricator.services.mozilla.com/D161377

accessible/tests/browser/e10s/browser.ini

@@ -18,8 +18,6 @@ support-files =
 
 # Caching tests
 [browser_caching_actions.js]
-skip-if =
-  (apple_catalina || apple_silicon) && !debug # Bug 1779541
 [browser_caching_attributes.js]
 [browser_caching_description.js]
 [browser_caching_document_props.js]

accessible/tests/browser/e10s/browser_caching_actions.js

@@ -259,7 +259,7 @@ addAccessibleTask(
   {
     chrome: true,
     topLevel: !isWinNoCache,
-    iframe: !isWinNoCache,
+    iframe: false, // Bug 1796846
-    remoteIframe: !isWinNoCache,
+    remoteIframe: false, // Bug 1796846
   }
 );