Fixed GEOSTest.test_emptyCollections() on GEOS 3.8.0.

It's a regression in GEOS 3.8.0 fixed in GEOS 3.8.1.

tests/gis_tests/geos_tests/test_geos.py

@@ -1127,6 +1127,8 @@ class GEOSTest(SimpleTestCase, TestDataMixin):
 
             # Testing __getitem__ (doesn't work on Point or Polygon)
             if isinstance(g, Point):
+                # IndexError is not raised in GEOS 3.8.0.
+                if geos_version_tuple() != (3, 8, 0):
                     with self.assertRaises(IndexError):
                         g.x
             elif isinstance(g, Polygon):