test-bot: test bottled dependents.

Test everything that `brew uses` a formula, has a bottle and a test.

This should allow some quick gains in terms of spotting formulae that may need
revisioned to avoid problems with shifting dependencies. As the test-bot lives
in a data centre with (very) fast internet the fetch and extraction time
shouldn't slow things down much.

Closes #35092.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>