CLN: remove internal usage of integer_array()
The `integer_array()` function stems from a time that `pd.array(..)` didn't exist yet. But since now `pd.array` can do this, IMO we shouldn't be using that outside of the integer module (eg I didn't add a `floating_array(..)`).

Only in `tests/arrays/integer/tst_construction.py` I still left the usage of `integer_array()` as is (but probably could also change it there). Could in principle remove the function altogether, since it is just a small wrapper around the private `arrays.integer.coerce_to_array`
>  need a whatsnew to mention that we are removing

This is not public, so no need for a whatnew I think? (I am only removing *internal* usage, there was no public exposure of this) > > need a whatsnew to mention that we are removing
> 
> This is not public, so no need for a whatnew I think? (I am only removing _internal_ usage, there was no public exposure of this)

i diagree this has been exposed for a while (in pandas.core.arrays), which is public-ish. i am ok with just removing it, but need to have a note. `pandas.core.arrays` is not public. The array classes *are* exposed, but in `pandas.arrays` (anyway, I won't further argue against adding a note if you insist (it's less work to write that sentence than writing this comment ;)), but just want to be clear this is something completely internal) > (anyway, I won't further argue against adding a note if you insist (it's less work to write that sentence than writing this comment ;)), but just want to be clear this is something completely internal)

thanks, i would also completely remove the usage of this as noted above. Yes, will update `test_construction.py` to stop using it as well @jorisvandenbossche i think this is worth putting on 1.2. ping when green. can you merge master >  i think this is worth putting on 1.2. 

Is there a reason to include it for 1.2? (since it's only an internal clean-up) > > i think this is worth putting on 1.2.
> 
> Is there a reason to include it for 1.2? (since it's only an internal clean-up)

no this is fine for 1.3. thanks