Clean up tempdir file used for gRPC server process to indicate success
Feedback from https://dagster.phacility.com/D5078 also applies here - get_system_temp_directory
The part about not using IPC to indicate subprocess startup may also apply but that's a bigger fix. We could have one file to indicate success and one file to indicate failure potentially though.
Test Plan: BK + Azure
Reviewed By: alangenfeld
Differential Revision: https://dagster.phacility.com/D5080