[LTP] min_free_kbytes: Handle transient memory drops in check_monitor

[Andrea Cervesato]

I also forgot that maybe you can check the TST_RETRY_FUNC
TST_RETRY_FN_EXP_BACKOFF usage. That might be suited for our usecase.

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Andrea Cervesato
SUSE QE Automation Engineer Linux
andrea.cervesato@suse.com