Update hsplit in np_array_ops.py
@JW1992 I passed the test you wrote, but may I ask where to put that test in? I don't think `np_array_ops_test.py` has any dynamic shape test. I wrote `testHVDSplit` like [jax's implementation](https://github.com/google/jax/blob/f337c00ed517d1ab012ac204d9974e167b33550c/tests/lax_numpy_test.py#L2757)
[numpy docs](https://numpy.org/doc/stable/reference/generated/numpy.hsplit.html): 
> hsplit is equivalent to split with axis=1, the array is always split along the second axis except for 1-D arrays, where it is split at axis=0.

As there is no testVsplit or testHsplit in `np_array_ops_test.py`, this fix doesn't need any test modification (and prob why the bug exists)