Applied to MultiIndex, to_frame() gives result with missing time component 
#### Code Sample, a copy-pastable example if possible

```python
rng = pd.date_range(start='1/1/2017', end='1/2/2017', freq='H')
numidx = list(range(5))
multi_idx = pd.MultiIndex.from_product([rng, numidx])
multi_idx.to_frame()
```
The `multi_idx.to_frame()` returns a correct output (partial output reproduced below):
![screen shot 2018-06-27 at 10 53 42 pm](https://user-images.githubusercontent.com/8138573/41982048-00306c60-7a5d-11e8-9198-9de0c5fa14a5.png)

However
```python
rng = pd.date_range(start='1/1/2017', end='1/2/2017', freq='H')
numidx2 = list(range(35))
multi_idx2 = pd.MultiIndex.from_product([rng, numidx2])
multi_idx2.to_frame()
```
`multi_idx2.to_frame()` will return the following where **the time info is missing**.  I expect that the time component should be retained as demonstrated by ``multi_idx.to_frame()``. This issue seems to happen when the size of second level (`list(range(35)`) of multi-index increases to a certain size?! 

![screen shot 2018-06-27 at 10 56 18 pm](https://user-images.githubusercontent.com/8138573/41982205-655e2ea6-7a5d-11e8-87e9-d75058db2886.png)

Could anyone helps to confirm is this a new issue? Thank you. 

#### Output of ``pd.show_versions()``
INSTALLED VERSIONS
------------------
commit: None
python: 3.5.2.final.0
python-bits: 64
OS: Darwin
OS-release: 17.5.0
machine: x86_64
processor: i386
byteorder: little
LC_ALL: en_US.UTF-8
LANG: en_US.UTF-8
LOCALE: en_US.UTF-8

pandas: 0.23.1
pytest: 3.0.5
pip: 10.0.1
setuptools: 38.4.0
Cython: 0.25.2
numpy: 1.14.1
scipy: 1.0.0
pyarrow: None
xarray: None
IPython: 6.4.0
sphinx: 1.5.1
patsy: 0.4.1
dateutil: 2.7.0
pytz: 2016.10
blosc: 1.5.1
bottleneck: 1.2.1
tables: 3.3.0
numexpr: 2.6.4
feather: None
matplotlib: 2.0.2
openpyxl: 2.4.0
xlrd: 1.0.0
xlwt: 1.1.2
xlsxwriter: 0.9.6
lxml: 3.6.4
bs4: 4.5.1
html5lib: 1.0.1
sqlalchemy: 1.1.4
pymysql: None
psycopg2: 2.7.4 (dt dec pq3 ext lo64)
jinja2: 2.9.5
s3fs: None
fastparquet: None
pandas_gbq: None
pandas_datareader: 0.2.1
