tests: test_running_base_functionality() failed on CI

[patapenka-alexey]

There is currently failed/flaky CI test. We need to fix it.

                with open(os.path.join(run_dir, inst, 'tarantool.pid')) as f:
>                   assert pidByInstanceName[inst] != f.readline()
E                   AssertionError: assert '40972' != '40972'
E                    +  where '40972' = <built-in method readline of _io.TextIOWrapper object at 0x7fe31c598860>()
E                    +    where <built-in method readline of _io.TextIOWrapper object at 0x7fe31c598860> = <_io.TextIOWrapper name='/tmp/pytest-of-runner/pytest-0/test_running_base_functionalit1/small_cluster_app/var/run/storage-master/tarantool.pid' mode='r' encoding='UTF-8'>.readline

test/integration/running/test_running_cluster.py:113: AssertionError
----------------------------- Captured stdout call -----------------------------
 INSTANCE                           STATUS   PID    MODE  CONFIG               BOX      UPSTREAM 
 small_cluster_app:storage-master   RUNNING  40954  RO    startup_in_progress  loading  --       
 small_cluster_app:storage-replica  RUNNING  40955  RO    startup_in_progress  loading  --       

   • The Instance small_cluster_app:storage-master (PID = 41009) has been terminated.
   • The Instance small_cluster_app:storage-replica (PID = 41010) has been terminated.

=========================== short test summary info ============================
FAILED test/integration/running/test_running_cluster.py::test_running_base_functionality - AssertionError: assert '40972' != '40972'
 +  where '40972' = <built-in method readline of _io.TextIOWrapper object at 0x7fe31c598860>()
 +    where <built-in method readline of _io.TextIOWrapper object at 0x7fe31c598860> = <_io.TextIOWrapper name='/tmp/pytest-of-runner/pytest-0/test_running_base_functionalit1/small_cluster_app/var/run/storage-master/tarantool.pid' mode='r' encoding='UTF-8'>.readline
===== 1 failed, 583 passed, 76 skipped, 44 deselected in 858.55s (0:14:18) =====
Error: running "python3 -m pytest -m not slow and not slow_ee and not notarantool test/integration" failed with exit code 1
Error: Process completed with exit code 1.

logs_29212819413.zip