#25707 - Fixed flakiness in stata write test
This is my first contribution, so please be gentle.
 
For future reference, this error occurs when the two files are written in different minutes. I couldn't break the comparison by feeding the test datetime objects that only changed the seconds, so I assume only the date, hours, and minutes, are encoded. 

Anyway, we can't pass `False` as a keyword argument for `time_stamp`. It defaults to `None`, which internally uses the current timestamp, but otherwise expects a datetime.

For testing purposes, it suffice to pass the same arbitrary timestamp as a keyword. That way it encodes the same timestamp into each file, regardless of when the test runs and how long it takes.

Instead of `False`, we could use a keyword argument like this: `{'time_stamp': pd.to_datetime('2019-01-01 00:00')}`

# [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/25714?src=pr&el=h1) Report
> Merging [#25714](https://codecov.io/gh/pandas-dev/pandas/pull/25714?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/dcf7fce19a662a86a2892396472e052ab9f69708?src=pr&el=desc) will **not change** coverage.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/25714/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/25714?src=pr&el=tree)

```diff
@@           Coverage Diff           @@
##           master   #25714   +/-   ##
=======================================
  Coverage   91.24%   91.24%           
=======================================
  Files         172      172           
  Lines       52967    52967           
=======================================
  Hits        48332    48332           
  Misses       4635     4635
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `89.82% <ø> (ø)` | :arrow_up: |
| #single | `41.74% <ø> (ø)` | :arrow_up: |


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> Powered by [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/25714?src=pr&el=footer). Last update [dcf7fce...af9ec8e](https://codecov.io/gh/pandas-dev/pandas/pull/25714?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 Thanks @gwrome! Nice job, and sorry about misleading you in the issue with the `time_stamp` argument type. You're welcome, glad I could help! 