Array.random.choice: handle array-like non-arrays

[gjoseph92]

In [1]: import dask.array as da

In [2]: import numpy as np

In [3]: np.random.choice([True, False], 4)
Out[3]: array([ True, False,  True, False])

In [4]: da.random.choice([True, False], 4)
---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
<ipython-input-4-33075a6cbfe5> in <module>()
----> 1 da.random.choice([True, False], 4)

/home/gabejoseph/.cache/bazel/_bazel_gabejoseph/cbd078f976ef86a52da9fe15f5a84af9/execroot/__main__/bazel-out/k8-opt/bin/descarteslabs/services/workbench/impl/repl.runf
iles/requirements_py3_pypi__dask_1_2_2_41_g32f0fac0/dask/array/random.py in choice(self, a, size, replace, p, chunks)
    201                     raise ValueError("a must be greater than 0")
    202             else:
--> 203                 a = asarray(a).rechunk(a.shape)
    204                 dtype = a.dtype
    205                 if a.ndim != 1:

AttributeError: 'list' object has no attribute 'shape'

• Tests added / passed
• Passes black dask / flake8 dask

[jakirkham]

cc @TomAugspurger

[jakirkham]

Thanks for the PR, @gjoseph92! This is great 😄