Decrease cardinality to stabilize tests

[macbre]

Run ANALYZE TABLE after setting up big table for tests.

For InnoDB tables, ANALYZE TABLE determines index cardinality by performing random dives on each of the index trees and updating index cardinality estimates accordingly. Because these are only estimates, repeated runs of ANALYZE TABLE could produce different numbers. This makes ANALYZE TABLE fast on InnoDB tables but not 100% accurate because it does not take all rows into account.

-- https://dev.mysql.com/doc/refman/8.0/en/analyze-table.html