tweak benchmark code

9 jobs for gridder_mr in 16 minutes and 23 seconds (queued for 1 second)
Status Job ID Name Coverage
  Build Docker
passed #783460
build_docker_from_cache

00:08:23

 
  Test
passed #783462
test_mpi

00:04:07

passed #783461
test_serial

00:04:57

80.0%
 
  Demo Runs
passed #783467
run_bernoulli

00:00:30

passed #783468
run_curve_fitting

00:00:29

passed #783464
run_getting_started_1

00:00:29

passed #783465
run_getting_started_2

00:01:14

passed #783466
run_getting_started_3

00:03:02

passed #783463
run_ipynb

00:01:25