Scheduler infinite loop after failed/canceled job

**Describe the bug**
See PR description at https://github.com/apache/arrow-ballista/pull/340

**To Reproduce**
See PR description at https://github.com/apache/arrow-ballista/pull/340

**Expected behavior**
A clear and concise description of what you expected to happen.

**Additional context**
Add any other context about the problem here.

Start by reading the linked PR 340 description, which contains the reproduction and context for the scheduler failure. Trace the scheduler behavior for failed and canceled jobs and verify that it terminates rather than entering an infinite loop.

Written by the indexing model from the issue text.