Fix relative imports for Python 3 (#27971)

* Fix relative imports for Python 3

* Remove space

* isort

tools/run_tests/python_utils/dockerjob.py

@@ -18,11 +18,13 @@ from __future__ import print_function
 import json
 import os
 import subprocess
+import sys
 import tempfile
 import time
 import uuid
 
-from . import jobset
+sys.path.append(os.path.dirname(os.path.abspath(__file__)))
+import jobset
 
 _DEVNULL = open(os.devnull, 'w')
 

tools/run_tests/python_utils/start_port_server.py

@@ -24,7 +24,8 @@ import time
 
 import six.moves.urllib.request as request
 
-from . import jobset
+sys.path.append(os.path.dirname(os.path.abspath(__file__)))
+import jobset
 
 # must be synchronized with test/core/util/port_server_client.h
 _PORT_SERVER_PORT = 32766