There have been a number of refactors around how options are passed into `MongoClient`, and it is quite clear that the refactoring is not yet complete. Recent attempts to remove deprecation warnings in the test suite have uncovered myriad cases where options are not being properly tracked (e.g. `validOptions` on the top level of MongoClient is woefully incomplete, and not even up to date with the jsdocs later in the same file).

We need to do a deep dive into supported options from top to bottom of the driver, adding many tests along the way.