Bug 1879952 - Fix test expectations with samesite=lax turned on r=tschuster

Differential Revision: https://phabricator.services.mozilla.com/D201639

testing/web-platform/meta/cookies/samesite/setcookie-navigation.https.html.ini

 [setcookie-navigation.https.html]
+  prefs: [network.cookie.sameSite.laxByDefault:true, network.cookie.sameSite.noneRequiresSecure:true]
   expected:
     if (os == "android") and fission: [OK, TIMEOUT]
   [Cross-site to same-site iframe navigation should only be able to set SameSite=None cookies.]
     expected: FAIL
-
-  [Same-site to cross-site-site iframe navigation should only be able to set SameSite=None cookies.]
-    expected: FAIL
-
-  [Cross-site to cross-site iframe navigation should only be able to set SameSite=None cookies.]
-    expected: FAIL