Investigate NODE-4444 - Clear timers from Node.JS module

NODE-4444 Description
Timers are now explicitly imported from the Node.js `timers` module as of https://github.com/mongodb/node-mongodb-native/pull/3275 (done as part of this ticket: https://jira.mongodb.org/browse/NODE-4281)

However, that change only enforced importing setting timers, not clearing timers, which could also diverge (and indeed I think this potentially causes confusing downstream behaviour when combined with eg sinon Fake Timers).

We should also require the corresponding timer clearing methods are imported from the Node.js module for consistency.