Fixed #28180 -- Numbered queries in assertNumQueries failure output

Thanks Tim Graham for the test part.

django/test/testcases.py

@@ -78,7 +78,7 @@ class _AssertNumQueriesContext(CaptureQueriesContext):
             "%d queries executed, %d expected\nCaptured queries were:\n%s" % (
                 executed, self.num,
                 '\n'.join(
-                    query['sql'] for query in self.captured_queries
+                    '%d. %s' % (i, query['sql']) for i, query in enumerate(self.captured_queries, start=1)
                 )
             )
         )

tests/test_utils/tests.py

@@ -323,8 +323,10 @@ class AssertNumQueriesContextManagerTests(TestCase):
         with self.assertRaises(AssertionError) as exc_info:
             with self.assertNumQueries(2):
                 Person.objects.count()
-        self.assertIn("1 queries executed, 2 expected", str(exc_info.exception))
-        self.assertIn("Captured queries were", str(exc_info.exception))
+        exc_lines = str(exc_info.exception).split('\n')
+        self.assertEqual(exc_lines[0], '1 != 2 : 1 queries executed, 2 expected')
+        self.assertEqual(exc_lines[1], 'Captured queries were:')
+        self.assertTrue(exc_lines[2].startswith('1.'))  # queries are numbered
 
         with self.assertRaises(TypeError):
             with self.assertNumQueries(4000):