Fix some macOS testsuite issues

tests/end2end/data/userscripts/stdinclose.py

@@ -1,4 +1,4 @@
-#!/usr/bin/python3
+#!/usr/bin/env python3
 # vim: ft=python fileencoding=utf-8 sts=4 sw=4 et:
 
 # Copyright 2017 Florian Bruhin (The Compiler) <mail@qutebrowser.org>

tests/end2end/features/yankpaste.feature

@@ -291,7 +291,6 @@ Feature: Yanking and pasting.
         # Compare
         Then the javascript message "textarea contents: onHello worlde two three four" should be logged
 
-    @qtwebengine_mac_xfail
     Scenario: Inserting text into a text field with undo
         When I set general -> log-javascript-console to info
         And I open data/paste_primary.html

tests/end2end/fixtures/quteprocess.py

@@ -74,6 +74,13 @@ def is_ignored_lowlevel_message(message):
     elif message == ('See the manual page for dbus-uuidgen to correct this '
                      'issue.'):
         return True
+    # Travis CI macOS:
+    # 2017-09-11 07:32:56.191 QtWebEngineProcess[5455:28501] Couldn't set
+    # selectedTextBackgroundColor from default ()
+
+    elif message.endswith("Couldn't set selectedTextBackgroundColor from "
+                          "default ()"):
+        return True
     return False