Due to certiain commands being run within `mongos_writes_wait_for_write_concern_timeseries.js` that have internal timeout of >60s in v8.0, they are from time to time failing the test, which leads to https://jira.mongodb.org/browse/BF-43252. Previous resolution to this problem was to reduce the amount of tests being run only to random 25%, as the failing commands won't be backported to v8.0. Therefore our new fix is to just reduce the window to 10% to ensure the probability of failing the test would be even smaller.