tt start/stop commands does not always work

[psergee]

Looks like this is some kind of race in start command. It does not start all instances under high load:

$ ../../tt/tt start myapp
   • Starting an instance [myapp:s1-master]...
   • Starting an instance [myapp:s1-replica]...
   • Starting an instance [myapp:s2-master]...
   • Starting an instance [myapp:s2-replica]...
   • Starting an instance [myapp:stateboard]...
   • Starting an instance [myapp:router]...
$ ../../tt/tt status myapp
   • myapp:s1-replica: ERROR. The process is dead
   • myapp:s2-master: RUNNING. PID: 48573.
   • myapp:s2-replica: RUNNING. PID: 48581.
   • myapp:stateboard: RUNNING. PID: 48585.
   • myapp:router: RUNNING. PID: 48595.
   • myapp:s1-master: ERROR. The process is dead

$ ../../tt/tt start myapp
   • Starting an instance [myapp:router]...
   • Starting an instance [myapp:s1-master]...
   • Starting an instance [myapp:s1-replica]...
   • Starting an instance [myapp:s2-master]...
   • Starting an instance [myapp:s2-replica]...
   • Starting an instance [myapp:stateboard]...
$ ../../tt/tt status myapp
   • myapp:s1-replica: RUNNING. PID: 48696.
   • myapp:s2-master: RUNNING. PID: 48700.
   • myapp:s2-replica: RUNNING. PID: 48701.
   • myapp:stateboard: ERROR. The process is dead
   • myapp:router: ERROR. The process is dead
   • myapp:s1-master: RUNNING. PID: 48691.

tt stop does not stop all instances:

$ ../../tt/tt stop myapp
   • the process is already dead. Error: "no such process"
   • The Instance myapp:s1-master (PID = 48691) has been terminated.
   • The Instance myapp:s1-replica (PID = 48696) has been terminated.
   • The Instance myapp:s2-master (PID = 48700) has been terminated.
   • The Instance myapp:s2-replica (PID = 48701) has been terminated.
   • the process is already dead. Error: "no such process"
$ ps awux | grep taran
user    48737  0.2  0.1 775644 25524 pts/4    Sl   16:02   0:00 tarantool stateboard.init.lua <running>

This issue reproduces on my system after the following commit:
4b0d12d tt: fix a race condition between tt start and tt stop

[psergee]

Log messages for dead processes:
stateboard:

2023-01-31 10:26:07.757 [10752] main I> entering the event loop
2023-01-31 10:28:22.772 [10752] main/114/iproto.shutdown I> tx_binary: stopped
2023-01-31 10:28:22.773 [10752] main/102/on_shutdown utils.c:489 E> LuajitError: stdin:290: variable 'close_sock_tr' is not declared
2023/01/31 10:28:22 Watchdog(INFO): the Instance has shutdown.

router:

2023-01-31 10:28:54.445 [10943] main I> entering the event loop
2023-01-31 10:29:40.556 [10943] main/102/on_shutdown utils.c:489 E> LuajitError: stdin:290: variable 'close_sock_tr' is not declared
2023/01/31 10:29:40 Watchdog(INFO): the Instance has shutdown.