[Integ-Test] Fix test_slurm_scaling

[hehe7318]

Description of changes

• Use c5.xlarge instead of hpc5a instance type. The slurm job is just sleep.
• We noticed bootstrap time in Rocky and Rhel is explicitly longer than other OSs. c5.xlarge bootstrap time in Rocky and Rhel is around 6 minutes. Set stop_max_delay_secs based on the OS. Increase wait_for_num_nodes_in_scheduler timeout to 7 mins.
• Ensure job running time bigger than _wait_for_node_reset timeout plus _assert_nodes_not_terminated waiting_time.
• Modify parameter name to improve readability
• Add a 45 seconds delay to accommodate node replacement process (~45s between node down status and replacement)

Tests

• Test re-run passed

Reference

• Cherry-pick from [Integ-Test] Fix test_slurm_scaling #6737

Checklist

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