Reduce flakiness of hyperloglog test
Reduce flakiness of hyperloglog test

This test occasionally flakes out because the count of the post-merge
hyperloglog is one less than the original one. That's just because
hyperloglogs are approximating, and with random input, we're bound to
land on some undercounting now and then.

stripe/veneur,gphat/veneur,stripe/veneur,evanj/veneur,evanj/veneur,gphat/veneur,gphat/veneur,evanj/veneur