rtla/tests: Show the command line for failing tests

Make investigating test failures a little bit easier by not having
to recreate the command line by looking in the test script.

Unfortunately, this doesn't capture variables set outside of the
command line, but it's better than nothing.

Signed-off-by: Crystal Wood <crwood@redhat.com>
Link: https://lore.kernel.org/r/20260919062756.819701-3-crwood@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>

tools/tracing/rtla/tests/engine.sh

@@ -86,6 +86,7 @@ check() {
 		else
 			# Add rtla output and exit code as comments in case of failure
 			echo "not ok $ctr - $1"
+			echo "# command: $RTLA" $2
 			echo -n "$failbuf"
 			echo "$result" | col -b | while read line; do echo "# $line"; done
 			printf "#\n# exit code %s\n" $exitcode