Re-enable 3 disabled tests

By updating the  single-tenant configuration, these existing tests can
be added back into service.

Change-Id: Ia4bdbd9853eb1709027f4d6f2d978590bd899409
Signed-off-by: Paul Belanger <pabelanger@redhat.com>

tests/fixtures/config/single-tenant/git/common-config/zuul.yaml

@@ -74,6 +74,12 @@
 
 - project:
     name: org/project
+    check:
+      jobs:
+        - project-merge:
+            jobs:
+              - project-test1
+              - project-test2
     gate:
       jobs:
         - project-merge:

tests/test_scheduler.py

@@ -1419,7 +1419,6 @@ jobs:
         for build in self.builds:
             self.assertEqual(build.parameters['ZUUL_VOTING'], '0')
 
-    @skip("Disabled for early v3 development")
     def test_check_queue_success(self):
         "Test successful check queue jobs."
 
@@ -1437,7 +1436,6 @@ jobs:
         self.assertEqual(self.getJobFromHistory('project-test2').result,
                          'SUCCESS')
 
-    @skip("Disabled for early v3 development")
     def test_check_queue_failure(self):
         "Test failed check queue jobs."
 
@@ -1639,7 +1637,6 @@ jobs:
         self.assertEqual(A.data['status'], 'MERGED')
         self.assertEqual(A.reported, 2)
 
-    @skip("Disabled for early v3 development")
     def test_new_patchset_dequeues_old(self):
         "Test that a new patchset causes the old to be dequeued"
         # D -> C (depends on B) -> B (depends on A) -> A -> M