Run Test Suites Against Serverless in Evergreen

Engineer(s): Andreas Summary: As part of the Serverless initiative, the Atlas Proxy will start presenting as a mongos to clients, while still being backed by a replica set. To make sure that this works as expected from the Drivers perspective, we should start running the Drivers tests against the "Proxy as a Mongos" to make sure that the Proxy behaves as expected. Cost in Eng Weeks: 4 Original | 2 To Date | 4 Est Final 2021-08-24: Pausing progress Work has paused since Andreas is on PTO until 8/30. Andreas will hand this off to the C / C++ team after he returns. PHP team was able to pass tests against serverless. That lowers the risk that C is not passing tests. 2021-07-13: Setting initial target end date to 2021-07-23 Andreas will resume work on this after the release. Hoping to make quicker progress since PHP is being tested at the same time