`lava-test-case --shell` waits for LAVA_ACK from the dispatcher after
each of these[1], but run-test-in-systemd does not. This is a point of
incompatibility that could potentially cause or exacerbate issues in
LAVA's "screen-scraping" on the serial console, such as
<https://bugs.apertis.org/show_bug.cgi?id=396>.

[1] https://git.linaro.org/lava/lava-dispatcher.git/blob/HEAD:/lava_dispatcher/lava_test_shell/lava-test-case

Differential Revision: https://phabricator.apertis.org/D388
Reviewed-by: araujo