Add a mongoq equivalent of MongoRunner.runMongos to allow starting mongoq in jstests. Test by updating the existing tests in jstests/serverless to use MongoRunner.runMongoq (see example).

We'll eventually create a ServerlessTest fixture similar to ShardingTest that uses MongoRunner.runMongoq to start its mongoq's, the way ShardingTest uses MongoRunner.runMongos to start its mongos's.