ARROW-5464: [Archery] Fix default diff --benchmark-filter
ARROW-5464: [Archery] Fix default diff --benchmark-filter

The default was left to `--benchmark-filter=^Regression`, this is a leftover from a refactor.

Author: François Saint-Jacques <fsaintjacques@gmail.com>

Closes #4434 from fsaintjacques/ARROW-5464-archery-default-filter and squashes the following commits:

b668efe51 <François Saint-Jacques> Remove leftover artefact

kou/arrow,laurentgo/arrow,wesm/arrow,wesm/arrow,icexelloss/arrow,xhochy/arrow,icexelloss/arrow,laurentgo/arrow,renesugar/arrow,icexelloss/arrow,renesugar/arrow,kou/arrow,laurentgo/arrow,icexelloss/arrow,kou/arrow,kou/arrow,apache/arrow,majetideepak/arrow,wesm/arrow,renesugar/arrow,majetideepak/arrow,majetideepak/arrow,apache/arrow,apache/arrow,wesm/arrow,icexelloss/arrow,apache/arrow,xhochy/arrow,majetideepak/arrow,majetideepak/arrow,apache/arrow,wesm/arrow,renesugar/arrow,cpcloud/arrow,laurentgo/arrow,kou/arrow,xhochy/arrow,xhochy/arrow,cpcloud/arrow,cpcloud/arrow,xhochy/arrow,icexelloss/arrow,kou/arrow,majetideepak/arrow,renesugar/arrow,kou/arrow,renesugar/arrow,xhochy/arrow,laurentgo/arrow,laurentgo/arrow,cpcloud/arrow,icexelloss/arrow,majetideepak/arrow,icexelloss/arrow,xhochy/arrow,majetideepak/arrow,renesugar/arrow,apache/arrow,icexelloss/arrow,renesugar/arrow,xhochy/arrow,renesugar/arrow,wesm/arrow,cpcloud/arrow,cpcloud/arrow,wesm/arrow,kou/arrow,apache/arrow,cpcloud/arrow,kou/arrow,icexelloss/arrow,kou/arrow,cpcloud/arrow,majetideepak/arrow,apache/arrow,xhochy/arrow,laurentgo/arrow,icexelloss/arrow,apache/arrow,majetideepak/arrow,wesm/arrow,renesugar/arrow,renesugar/arrow,wesm/arrow,laurentgo/arrow,cpcloud/arrow,wesm/arrow,kou/arrow,xhochy/arrow,laurentgo/arrow,laurentgo/arrow,majetideepak/arrow,renesugar/arrow,majetideepak/arrow,renesugar/arrow,icexelloss/arrow,wesm/arrow,renesugar/arrow,apache/arrow,renesugar/arrow,majetideepak/arrow,laurentgo/arrow,apache/arrow,wesm/arrow,laurentgo/arrow,kou/arrow,wesm/arrow,wesm/arrow,kou/arrow,majetideepak/arrow,xhochy/arrow,cpcloud/arrow,laurentgo/arrow,cpcloud/arrow,xhochy/arrow,cpcloud/arrow,apache/arrow,cpcloud/arrow,cpcloud/arrow,xhochy/arrow,xhochy/arrow,xhochy/arrow,apache/arrow,laurentgo/arrow,laurentgo/arrow,kou/arrow,icexelloss/arrow,majetideepak/arrow,apache/arrow,icexelloss/arrow