Run isort with two jobs to speed it up.

Skip files that cause a bug in isort as a workaround.

tox.ini

@@ -87,4 +87,8 @@ commands =
     pydocstyle {toxinidir}/celery
 
 [testenv:isort-check]
+<<<<<<< HEAD
 commands = isort --project celery --diff --order-by-type -rc -c {toxinidir}/celery {toxinidir}/t
+=======
+commands = isort -j2 --diff --skip celery/utils/deprecated.py --project celery --order-by-type -rc -c {toxinidir}/celery {toxinidir}/t
+>>>>>>> Run isort with two jobs to speed it up.