StopOnExitJobServer interrupt handler errors

When I cancelled a job using FlinkRunner, I got the error: `TypeError: stop() takes exactly 1 argument (3 given)` which is an error with this line: [https://github.com/apache/beam/blob/c5f43342f914fc8ff367b86fb9294c38436ed3ce/sdks/python/apache_beam/runners/portability/job_server.py#L87](https://github.com/apache/beam/blob/c5f43342f914fc8ff367b86fb9294c38436ed3ce/sdks/python/apache_beam/runners/portability/job_server.py#L87)

However, it appears the job server was closed successfully, presumably on exit. Which raises the question, why do we attempt to handle interrupts at all?

Imported from Jira [BEAM-8310](https://issues.apache.org/jira/browse/BEAM-8310). Original Jira may contain additional context.
Reported by: ibzib.