tests: speedup test_workflow.test_run_new_all
tests: speedup test_workflow.test_run_new_all

From 160s to 60s by running only one benchmark and reinstall a backup of
initial results and skipping existing commit (for ALL spec).

Also remove unneeded --skip-existing-{succesful,failed} in first commit
run.

pv/asv,airspeed-velocity/asv,pv/asv,airspeed-velocity/asv,airspeed-velocity/asv,airspeed-velocity/asv,qwhelan/asv,pv/asv,qwhelan/asv,pv/asv,qwhelan/asv,spacetelescope/asv,spacetelescope/asv,spacetelescope/asv,qwhelan/asv,spacetelescope/asv