Describe the bug
https://github.com/bats-core/bats-core/blob/master/test/parallel.bats#L12 seems to assume that GNU parallel exists on the system. But it never checks that the parallel program
is indeed the GNU parallel program, vs the other parallel from moreutils in Ubuntu for example. (History apparently here: https://www.gnu.org/software/parallel/history.html)

To Reproduce
Steps to reproduce the behavior:

1. See here: https://github.com/filmil/bazel-bats/actions/runs/3246348635/jobs/5567182637

Expected behavior
The test passes.

Environment (please complete the following information):

• Bats Version 1.5.0
• OS: Ubuntu
• Bash version: ?

Additional context

GNU parallel has a flag --jobs which the test uses. But, the moreutils parallel has only the short form -j. So when test/parallel.bats tests for the existence of the parallel binary, it never checks whether it also supports --jobs, leading to test failures if the parallel binary is not GNU parallel.

filmil/bazel-bats#9 (comment) explains the details.