MAINT: Nicer error msg for NULL byte in read_csv
Provides a nicer error message for the Python engine in `read_csv` when the data contains a `NULL` byte.

Closes #2741.

## [Current coverage](https://codecov.io/gh/pydata/pandas/pull/13859?src=pr) is 85.25% (diff: 100%)

> Merging [#13859](https://codecov.io/gh/pydata/pandas/pull/13859?src=pr) into [master](https://codecov.io/gh/pydata/pandas/branch/master?src=pr) will increase coverage by **<.01%**

``` diff
@@             master     #13859   diff @@
==========================================
  Files           140        140          
  Lines         50455      50460     +5   
  Methods           0          0          
  Messages          0          0          
  Branches          0          0          
==========================================
+ Hits          43014      43019     +5   
  Misses         7441       7441          
  Partials          0          0          
```

> Powered by [Codecov](https://codecov.io?src=pr). Last update [59f2557...bce0b6b](https://codecov.io/gh/pydata/pandas/compare/59f25575f42e19f066dc3cd2245983071e2d7813...bce0b6b932555e957363ca78e61a0d266d077997?src=pr)
 thanks @gfyoung 
