Add dir prefix to run run-cmucl.sh

Use ./run-cmucl.sh instead of run-cmucl.sh since . is probably not in
$PATH.
2 jobs for rtoy-issue-87-add-cl-bench in 11 minutes and 17 seconds (queued for 2 seconds)
Status Name Job ID Coverage
  Test
passed linux-runner #4262
linux

00:06:59

passed osx-runner #4263
osx

00:11:17