Spawn connection-checker as an unprivileged user

[dlon]

test-runner now spawns all processes as an unprivileged user.

Fix DES-1131
Fix DES-1129

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This change is 

[linear]

DES-1131 Fix apparent leak in `test_mul_02_002`

DES-1129 `test_mul_02_002` fails on macOS

[hulthe]

Reviewed 5 of 6 files at r1, all commit messages.
Reviewable status: 5 of 6 files reviewed, 2 unresolved discussions (waiting on @dlon)

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-- commits line 9 at r1:
👌

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test/test-runner/src/util.rs line 84 at r1 (raw file):

            log::error!("Failed to restore uid: {error}");
        }
    });

Nice work with the drop guards. They should take care of any bugs if func panics too, right?

[dlon]

Reviewable status: 4 of 6 files reviewed, 1 unresolved discussion (waiting on @hulthe)

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test/test-runner/src/util.rs line 84 at r1 (raw file):

Previously, hulthe (Joakim Hulthe) wrote…

Nice work with the drop guards. They should take care of any bugs if func panics too, right?

Yep. Probably not too important in reality, since the runner would crash and (hopefully) be restarted anyway.

[hulthe]

Reviewed 1 of 6 files at r1, 1 of 1 files at r2, all commit messages.
Reviewable status: all files reviewed, 1 unresolved discussion