Re #9351. Up the required memory to stop this running (and failing)

on our 8GB Windows test machine.
Re #9351. Up it more - it's still going managed in places.
Re #9351. This one appears to go to swap in places as well.

Which includes my 16GB Mac Pro, so set the limit accordingly.
Merge remote-tracking branch 'origin/feature/9351_up_required_memory_for_multirep_test'