[1.9.x] Fixed #25592 -- Fixed misnamed strictly_above PostGIS lookup

Fixes a regression from 2bd1bbc42. Thanks Daniel Wiesmann for the report
and Tim Graham for the review.
Backport of c08f85fd54 from master.

tests/gis_tests/utils.py

@@ -1,13 +1,30 @@
-from unittest import skip
+import unittest
+from functools import wraps
 
 from django.conf import settings
-from django.db import DEFAULT_DB_ALIAS
+from django.db import DEFAULT_DB_ALIAS, connection
+
+
+def skipUnlessGISLookup(*gis_lookups):
+    """
+    Skip a test unless a database supports all of gis_lookups.
+    """
+    def decorator(test_func):
+        @wraps(test_func)
+        def skip_wrapper(*args, **kwargs):
+            if any(key not in connection.ops.gis_operators for key in gis_lookups):
+                raise unittest.SkipTest(
+                    "Database doesn't support all the lookups: %s" % ", ".join(gis_lookups)
+                )
+            return test_func(*args, **kwargs)
+        return skip_wrapper
+    return decorator
 
 
 def no_backend(test_func, backend):
     "Use this decorator to disable test on specified backend."
     if settings.DATABASES[DEFAULT_DB_ALIAS]['ENGINE'].rsplit('.')[-1] == backend:
-        @skip("This test is skipped on '%s' backend" % backend)
+        @unittest.skip("This test is skipped on '%s' backend" % backend)
         def inner():
             pass
         return inner