Larger unit tests collect a lot of events, which are just processed
on shutdown. But since the Scheduler is just an unsorted linked
list, processing these in order is O(n^2) for lookup, which really
adds up, e.g. sw_ooxmlexport8 has 35047 tasks on shutdown.

So this just processes all pending events before running each unit
test.

Also adds missing spellchecking components to some calc tests.

Change-Id: Icf12146015afc17a1f52f79c18f248b72650ad46
Reviewed-on: https://gerrit.libreoffice.org/43199Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Jan-Marek Glogowski <glogow@fbihome.de>