When working with pivot cache there's alternating use of
locale dependent and locale indepentent formats, which
causes unnecessary loading of calendars due to constant
switching.

OnDemandLocaleDataWrapper already does this, now do
something similar in OnDemandCalendarWrapper.

Change-Id: I3d64dbe8afa929cf416d87678762e82b45561d63
Reviewed-on: https://gerrit.libreoffice.org/39762Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>
Tested-by: Noel Grandin <noel.grandin@collabora.co.uk>