CLN: ASV ctors benchmark
I think this these asvs should be enhanced or reorganized to other files in the future, but in the meantime:

- Added `np.random.seed(1234)` in setup classes where random data is created xref #8144

- Ran flake8 and replaced star imports

```
$ asv run -q -b ^ctors
[  0.00%] ·· Benchmarking conda-py3.6-Cython-matplotlib-numexpr-numpy-openpyxl-pytables-pytest-scipy-sqlalchemy-xlrd-xlsxwriter-xlwt
[ 20.00%] ··· Running ctors.Constructors.time_dtindex_from_index_with_series                                         99.0μs
[ 40.00%] ··· Running ctors.Constructors.time_dtindex_from_series                                                    59.5μs
[ 60.00%] ··· Running ctors.Constructors.time_frame_from_ndarray                                                      237μs
[ 80.00%] ··· Running ctors.Constructors.time_index_from_array_string                                                 101μs
[100.00%] ··· Running ctors.Constructors.time_series_from_ndarray                                                    61.2μs
```

# [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/18479?src=pr&el=h1) Report
> Merging [#18479](https://codecov.io/gh/pandas-dev/pandas/pull/18479?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/412988ed972a929203b2e867c8fdc7fcb0e7d312?src=pr&el=desc) will **decrease** coverage by `0.01%`.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/18479/graphs/tree.svg?height=150&width=650&token=eZ4WkYLtcO&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/18479?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #18479      +/-   ##
==========================================
- Coverage   91.34%   91.32%   -0.02%     
==========================================
  Files         163      163              
  Lines       49717    49717              
==========================================
- Hits        45413    45404       -9     
- Misses       4304     4313       +9
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `89.12% <ø> (ø)` | :arrow_up: |
| #single | `40.51% <ø> (-0.07%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/18479?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/io/gbq.py](https://codecov.io/gh/pandas-dev/pandas/pull/18479?src=pr&el=tree#diff-cGFuZGFzL2lvL2dicS5weQ==) | `25% <0%> (-58.34%)` | :arrow_down: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/18479?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `97.8% <0%> (-0.1%)` | :arrow_down: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/18479?src=pr&el=continue).
> **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta)
> `Δ = absolute <relative> (impact)`, `ø = not affected`, `? = missing data`
> Powered by [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/18479?src=pr&el=footer). Last update [412988e...01c854e](https://codecov.io/gh/pandas-dev/pandas/pull/18479?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 thanks!