chore: speed up testing

[conradludgate]

safekeeper::random_test test_random_schedules debug test takes over 2 minutes to run on our arm runners. Running it 6 times with pageserver settings seems redundant.

[conradludgate]

before:
https://github.com/neondatabase/neon/actions/runs/10616691322/job/29427779308 took 24m12s with 15m38s spent on rust tests.

after:
https://github.com/neondatabase/neon/actions/runs/10630378997/job/29469298707 took 19m24s with 9m41s spent on rust tests.

[koivunej]

Clearly an oversight of re-running it so many times.

[github-actions]

3801 tests run: 3695 passed, 0 failed, 106 skipped (full report)

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Flaky tests (1)

Postgres 16

• test_subscriber_restart: debug-x86-64

Code coverage* (full report)

• functions: 32.5% (7416 of 22809 functions)
• lines: 50.6% (60043 of 118588 lines)

* collected from Rust tests only

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_{The comment gets automatically updated with the latest test results
5a199e1 at 2024-08-30T10:32:25.691Z :recycle:}