[QUARANTINE] The test_backfill_job.py causes resource (probably memory) exhaustion

[potiuk]

Apache Airflow version:
master

We often have "Exit 137" which is likely memory exhaustion cause by the test_backfill_job.py. It's been investigated by GitHub support (we've enabled debugging and waiting to reoccur). See #11294

Example here:

https://github.com/apache/airflow/runs/1245441164?check_suite_focus=true#step:6:301

Most likely it is caused by backfill job trying to backfill too much ?

How to reproduce it:

Anything else we need to know:

[potiuk]

This started happening a lot less afer we split the tests. Closing.

[ashb]

I'm still seeing this a noticeable amount of the time :(