Respect cgroups v2 "low" memory limit

[shughes-uk]

• Tests added / passed
• Passes pre-commit run --all-files

Missed an option for cgroups v2. Reference for it is here https://facebookmicrosites.github.io/cgroup2/docs/memory-controller.html

Real world usage of this is someone running docker with the "memory-reservation" parameter set

https://docs.docker.com/config/containers/resource_constraints/

Ideally dask should work to stay under it, but will not punished if exceeded.

Possibly dask could ignore this limit, but I suspect users will have a sad time to see dask going up to their harder limits and being OOM killed.

[GPUtester]

Can one of the admins verify this patch?

Admins can comment ok to test to allow this one PR to run or add to allowlist to allow all future PRs from the same author to run.

[github-actions]

Unit Test Results

See test report for an extended history of previous test failures. This is useful for diagnosing flaky tests.

       20 files   -        1         20 suites   - 1   9h 58m 11s ⏱️ - 1h 2m 26s
  3 849 tests +       1    3 740 ✔️ +       2     107 💤 ±  0  2 ❌  - 1 
35 828 runs   - 1 375  34 091 ✔️  - 1 313  1 735 💤  - 61  2 ❌  - 1 

For more details on these failures, see this check.

Results for commit 4e58bda. ± Comparison against base commit 14b2360.

[hendrikmakait]

add to allowlist

[hendrikmakait]

Thanks, @shughes-uk!