Bug 1549855 - remove references to e10s force-enable pref that is no longer used, r=ato,eeejay

Differential Revision: https://phabricator.services.mozilla.com/D31417

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

accessible/tests/browser/head.js

@@ -15,8 +15,7 @@ function setE10sPrefs() {
   return new Promise(resolve =>
     SpecialPowers.pushPrefEnv({
       set: [
-        ["browser.tabs.remote.autostart", true],
-        ["browser.tabs.remote.force-enable", true]
+        ["browser.tabs.remote.autostart", true]
       ]
     }, resolve));
 }

testing/marionette/harness/marionette_harness/runner/base.py

@@ -571,7 +571,6 @@ class BaseMarionetteTestRunner(object):
         if self.e10s:
             self.prefs.update({
                 'browser.tabs.remote.autostart': True,
-                'browser.tabs.remote.force-enable': True,
             })
 
         # If no repeat has been set, default to 30 extra runs

testing/marionette/harness/marionette_harness/tests/harness_unit/test_marionette_runner.py

@@ -458,7 +458,6 @@ def test_option_e10s_sets_prefs(mach_parsed_kwargs, e10s):
     runner = MarionetteTestRunner(**mach_parsed_kwargs)
     e10s_prefs = {
         'browser.tabs.remote.autostart': True,
-        'browser.tabs.remote.force-enable': True,
     }
     for k,v in e10s_prefs.iteritems():
         assert runner.prefs.get(k, False) == (v and e10s)