Make tests pass in fast_compile.

theano/sandbox/gpuarray/tests/test_subtensor.py

@@ -26,4 +26,6 @@ class G_subtensor(T_subtensor):
                              dtype='float32',
                              ignore_topo=(HostFromGpu, GpuFromHost,
                                           DeepCopyOp))
+        # GPU opt can't run in fast_compile only.
+        self.fast_compile = False
         assert self.sub == GpuSubtensor