make dir on prepare step

Signed-off-by: Andrey Berezin <a.berezin@yadro.com>

src/frostfs_testlib/load/k6.py

@@ -153,6 +153,9 @@ class K6:
 
     @reporter.step_deco("Start K6 on initiator")
     def start(self) -> None:
+        # Make working_dir directory
+        self.shell.exec(f"mkdir -p {self.load_params.working_dir}")
+
         command = (
             f"{self._k6_dir}/k6 run {self._generate_env_variables()} "
             f"{self._k6_dir}/scenarios/{self.scenario.value}.js"