TST: Add another test for uneven CSV rows
Title is self-explanatory.

xref #15066.
Closes #9549.

## [Current coverage](https://codecov.io/gh/pandas-dev/pandas/pull/15114?src=pr) is 84.75% (diff: 100%)
> Merging [#15114](https://codecov.io/gh/pandas-dev/pandas/pull/15114?src=pr) into [master](https://codecov.io/gh/pandas-dev/pandas/branch/master?src=pr) will not change coverage

```diff
@@             master     #15114   diff @@
==========================================
  Files           145        145          
  Lines         51232      51232          
  Methods           0          0          
  Messages          0          0          
  Branches          0          0          
==========================================
  Hits          43420      43420          
  Misses         7812       7812          
  Partials          0          0          
```

> Powered by [Codecov](https://codecov.io?src=pr). Last update [0fe491d...303c340](https://codecov.io/gh/pandas-dev/pandas/compare/0fe491db358204544814aa2371fed4ea947532ab...303c340da125b4ac690b687baf5a3071217bdaef?src=pr) @gfyoung Is this kind of CSV currently untested? It is, but to be safe we always include test cases from issues we close. > It is, but to be safe we always include test cases from issues we close.

Indeed, we do, but in this case it does seem like almost exactly the same test as the one above but with different numbers? (only usage of header or not, but I don't think this should matter?) @jorisvandenbossche : It shouldn't, but more tests couldn't hurt :smile: @gfyoung I also changed the 'closes ..', as I would like to keep the issue open for the discussion about the `bad_lines` keyword in there. Will update the title over there @jorisvandenbossche : I'm changing it back because #5986 and #9729 are better places to have this IMO (we should de-duplicate discussions if possible). > more tests couldn't hurt

more tests start to hurt when we don't see the wood for the trees anymore And changed in back again :-) 
#9729 is about too few fields, not about processing rows with too many. 
#5986 is probably a wrong link?

But maybe its better to just open a new issue about it and refer to the other ones. @jorisvandenbossche : Meant #5686 (sorry!) 

I don't fully understand what you said there (might be the forest-trees idiom) > I don't fully understand what you said there (might be the forest-trees idiom)

yet I looked it up before posting to be sure it was correct English :-) http://dictionary.cambridge.org/dictionary/english/not-see-the-wood-for-the-trees. With too many tests, it is more difficult to keep the overview