Change yield type used by range deleter from YIELD_MANUAL to YIELD_AUTO

Currently, when deleting batches of documents (default 128) the range deleter only yields manually. This is different behavior than regular bulk deletes, which yield on time as well.

The range deleter should also yield on time, making it functionally equivalent to regular bulk deletes. Failing to do so could result in locks being held and blocking other operations longer than anticipated in a case where range deletion was unexpectedly slow (due to an i/o bottleneck, for example).