PEP8: import of built-in modules at the top of the file

This also prevents double import of `sys` and `os`.

benchmark/farm.py

@@ -1,13 +1,16 @@
 #!/usr/bin/env python3
 
+import argparse
+import datetime
+import json
 import os
+import shutil
 import sys
+import tempfile
 
 SCRIPT_PATH = os.path.realpath(__file__)
 SCRIPT_DIR = os.path.dirname(SCRIPT_PATH)
 
-import argparse
-import datetime
 import foundation
 from foundation import (benchrunner,
                         buildbot,
@@ -16,11 +19,6 @@ from foundation import (benchrunner,
                         logger,
                         system_info,
                         util)
-import json
-import os
-import shutil
-import sys
-import tempfile
 
 
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