Add teardowns in asv benchmarks

[louispotok]

Per @jreback's comment here, we should have teardowns in asv benchmarks, especially in IO benchmarks where we are creating files.

[jreback]

to be clear, its mainly the io benchmarks or anything that generates an on-disk artifact.

[brychlicki-reef]

The comment above references dead link.
So I spent some time familiarizing myself with the original issue and looking for the comment that triggered this issue. Found it, leaving here as back reference so that others don't have go the long way.

A PR for this is on its way from us.

[jreback]

@brychlicki-reef thanks! that would be great

[prudhv16]

is any one working on it, else could I try this please ?