repeat detailedGC also if provided scope not fully processed

Currently needrepeat is not set if the provided (detailedGC) scope is "complete", i.e. is reaching the oldest checkpoint or now - maxTimeMillis.

However, in particular for the initial detailedGC run, the PROGRESS_BATCH_SIZE will likely be hit and thus prevent the full scope to be scanned.

A repetition of GC will continue from where the batch-interrupted previous run left off, however the needrepeat is not correctly set in this case.