flake: delete ticker test

Created by: rvantonder

This is a proposal. I ran into this twice in the last couple of days and propose that it would be better to delete the test until it can be revised to be less flakey. I have no context on this test (don't know if it's infra or not, don't know what acceptable ranges are here, etc).

(1) https://github.com/sourcegraph/sourcegraph/pull/20881#issuecomment-841485128 (2) https://buildkite.com/sourcegraph/sourcegraph/builds/96414#e4aae0db-2584-45eb-9503-652414047b69/241-242