Currently RemoteCommandTargeter::selectFindHostMaxWaitTime() will always return a default timeout:

https://github.com/mongodb/mongo/blob/master/src/mongo/client/remote_command_targeter.cpp#L48-L49

This is the timeout which we use when targeting a particular host within a shard. Instead of using a default, we should attach a timeout to the OperationContext (potentially the maxTimeMS value) and use this as the host targeting timeout.