nixos/test-driver: Remove single-use trivial utility method (#470477)

nixos/lib/test-driver/src/test_driver/machine/__init__.py

@@ -790,9 +790,6 @@ class Machine:
     def stop_job(self, jobname: str, user: str | None = None) -> tuple[int, str]:
         return self.systemctl(f"stop {jobname}", user)
 
-    def wait_for_job(self, jobname: str) -> None:
-        self.wait_for_unit(jobname)
-
     def connect(self) -> None:
         def shell_ready(timeout_secs: int) -> bool:
             """We sent some data from the backdoor service running on the guest

nixos/tests/mysql/mysql-autobackup.nix

@@ -52,7 +52,7 @@ let
 
         with subtest("Do a backup and wait for it to start"):
             machine.start_job("automysqlbackup.service")
-            machine.wait_for_job("automysqlbackup.service")
+            machine.wait_for_unit("automysqlbackup.service")
 
         with subtest("wait for backup file and check that data appears in backup"):
             machine.wait_for_file("/var/backup/mysql/daily/testdb")