run-test-in-systemd: stop emitting STARTTC, ENDTC

`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

common/run-test-in-systemd

@@ -261,10 +261,6 @@ debug "reloading via ${systemctl} daemon-reload"
 ${systemctl} daemon-reload
 ${systemctl} stop ${service} || :
 
-if [ -n "${lava_runes}" ]; then
-    echo "<LAVA_SIGNAL_STARTTC ${name}>"
-fi
-
 debug "starting test"
 
 # Watch the output in real time, both for developers' benefit and so that
@@ -295,7 +291,6 @@ wait "$cat_fifo_pid" || result=fail
 rm -fr "${user_log_dir}" || result=fail
 
 if [ -n "${lava_runes}" ]; then
-    echo "<LAVA_SIGNAL_ENDTC ${name}>"
     "lava-test-case" "${name}" --result "${result}"
 fi