test/system: Unbreak the downstream Fedora CI

[debarshiray]

The working directory from which bats(1) is invoked might not be part of the Toolbx container. eg., the downstream Fedora CI invokes the tests as:

  $ cd /path/to/toolbox/test/system
  $ bats .

... and it led to:

  not ok 8 help: Try unknown command (forwarded to host)
  # tags: commands-options
  # (from function `assert_line' in file
      ./libs/bats-assert/src/assert.bash, line 488,
  #  in test file ./002-help.bats, line 135)
  #   `assert_line --index 0
        "Error: unknown command \"foo\" for \"toolbox\""' failed
  #
  # -- line differs --
  # index    : 0
  # expected : Error: unknown command "foo" for "toolbox"
  # actual   : Error: crun: chdir to `/usr/share/toolbox/test/system`:
      No such file or directory: OCI runtime attempted to invoke a
      command that was not found
  # --
  #

[softwarefactory-project-zuul]

Build succeeded.
https://softwarefactory-project.io/zuul/t/local/buildset/84cdacf6576e4f01a884991c6d277249

✔️ unit-test SUCCESS in 5m 42s
✔️ unit-test-migration-path-for-coreos-toolbox SUCCESS in 3m 47s
✔️ unit-test-restricted SUCCESS in 5m 56s
✔️ system-test-fedora-rawhide-commands-options SUCCESS in 1h 40m 52s
✔️ system-test-fedora-rawhide-runtime-environment-arch-fedora SUCCESS in 1h 45m 59s
✔️ system-test-fedora-rawhide-runtime-environment-ubuntu SUCCESS in 59m 14s
✔️ system-test-fedora-41-commands-options SUCCESS in 56m 06s
✔️ system-test-fedora-41-runtime-environment SUCCESS in 1h 14m 05s
✔️ system-test-fedora-40-commands-options SUCCESS in 58m 13s
✔️ system-test-fedora-40-runtime-environment SUCCESS in 1h 14m 46s
✔️ system-test-fedora-39-commands-options SUCCESS in 58m 47s
✔️ system-test-fedora-39-runtime-environment SUCCESS in 1h 17m 28s