Bug 1605572 - Add release or beta expectations for appcache-iframe.ht…

…tps.html and sub-tests. r=mattwoodrow

Differential Revision: https://phabricator.services.mozilla.com/D58224

--HG--
extra : moz-landing-system : lando

testing/web-platform/meta/html/browsers/offline/appcache/appcache-iframe.https.html.ini

@@ -4,11 +4,15 @@
     if nightly_build: https://bugzilla.mozilla.org/show_bug.cgi?id=1583700
   expected:
     if fission: TIMEOUT
+    if release_or_beta: ["TIMEOUT", "OK"]
+
   [iframe should be loaded from application caches for fallback.]
     expected:
       if fission: TIMEOUT
+      if release_or_beta: ["TIMEOUT", "PASS"]
 
   [iframe should be loaded from application caches.]
     expected:
       if fission: FAIL
+      if release_or_beta: ["FAIL", "PASS"]