test: allocate at least one logical core per unit test
test: allocate at least one logical core per unit test

Currently, we only allocate memory for concurrent unit test runs. This can cause
CPU overcommit when running test.py on machines with a log of memory but few cores.
This overcommit can cause timeouts in tests that are time-sensitive (bad practice,
but can happen) and makes the desktop sluggish.

Improve by allocating at least one logical core per running test.

Reviewed-by: Benny Halevy <23c997c90eb8537635e9392d48e7af1bf1b2ca22@scylladb.com>
Message-Id: <a39938281c004795731ceb579089ad4f5263638f@scylladb.com>

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