Remove duplicate tests. No need to retest them all in 2d and 4d. Fusion don't…

theano/tensor/tests/test_opt.py

@@ -1178,7 +1178,7 @@ class test_fusion(unittest.TestCase):
         mode._optimizer = mode._optimizer.including(
             'local_elemwise_fusion', 'composite_elemwise_fusion',
             'canonicalize')
-        self.do(mode, self._shared, shp)
+        self.do(mode, self._shared, shp, slice=slice(0, 1))
 
     def test_fusion_35inputs(self):
         # Make sure a fused graph with more than 35 inputs does not segfault