[vstest] Only collect stdout of orchagent_restart_check in vstest (sonic-net#2597)

* Only collect stdout of orchagent_restart_check in vstest

Author: bingwang-ms

tests/conftest.py

@@ -601,7 +601,7 @@ def restart(self) -> None:
         self.check_ready_status_and_init_db()
 
     def runcmd(self, cmd: str, include_stderr=True) -> Tuple[int, str]:
-        res = self.ctn.exec_run(cmd)
+        res = self.ctn.exec_run(cmd, stdout=True, stderr=include_stderr)
         exitcode = res.exit_code
         out = res.output.decode("utf-8")
 

tests/test_storm_control.py

@@ -211,7 +211,7 @@ def test_warm_restart_all_interfaces(self,dvs,testlog):
         dvs.warm_restart_swss("true")
 
         # freeze orchagent for warm restart
-        (exitcode, result) = dvs.runcmd("/usr/bin/orchagent_restart_check")
+        (exitcode, result) = dvs.runcmd("/usr/bin/orchagent_restart_check", include_stderr=False)
         assert result == "RESTARTCHECK succeeded\n"
         time.sleep(2)