tests: enable qubes.tests.int.basic

It is fully converted to core3 API (or tests marked as 'skip' if not),
so can be reenabled.

qubes/tests/__init__.py

@@ -771,7 +771,7 @@ def load_tests(loader, tests, pattern): # pylint: disable=unused-argument
             'qubes.tests.tools',
 
             # integration tests
-#           'qubes.tests.int.basic',
+            'qubes.tests.int.basic',
 #           'qubes.tests.dom0_update',
 #           'qubes.tests.network',
 #           'qubes.tests.vm_qrexec_gui',