Could not find a single instance where the return value of
SwCacheAccess::Get() was actually checked, so let's have
SwCache::Insert() automatically resize the cache, since it starts
out with just 100 capacity; also, check that the size doesn't overflow.

Change-Id: I3cd7cf2aea79e01816b12e4dbaf79c3bf82bf8fe
Reviewed-on: https://gerrit.libreoffice.org/49140Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Michael Stahl <mstahl@redhat.com>