Bug 1304178 - Reset the splitconsole pref after every test to make sure it gets cleaned up;r=linclark

MozReview-Commit-ID: Bt7KrCXaUwV

devtools/client/framework/test/shared-head.js

@@ -96,6 +96,7 @@ registerCleanupFunction(() => {
   Services.prefs.clearUserPref("devtools.dump.emit");
   Services.prefs.clearUserPref("devtools.toolbox.host");
   Services.prefs.clearUserPref("devtools.toolbox.previousHost");
+  Services.prefs.clearUserPref("devtools.toolbox.splitconsoleEnabled");
 });
 
 registerCleanupFunction(function* cleanup() {