Startup and shutdown is an area without much direct unit test coverage. We should add at least the following tests:

• mongod startup followed immediately by shutdown with no command line arguments
• The shutdownAtStartup failpoint present in mongod makes this easy

• mongos startup followed immediately by shutdown with no command line arguments
• A failpoint similar to shutdownAtStartup can be added in the mongos startup

• mongod startup followed immediately by shutdown with --shardsvr
• mongod startup followed immediately by shutdown with --configsvr
• mongod startup followed immediately by shutdown with --maintenanceMode=standalone