Please support indexing with 0 dim np.array in df.iloc.

#### Code Sample, a copy-pastable example if possible

The code below works correctly.
```python
df=pd.DataFrame([[1,2],[3,4]])
df.iloc[np.array([0])]
```
But the code below raises an error.
```python
df.iloc[np.array(0)]
```
```
TypeError: object of type 'numpy.int64' has no len()
```