tdf#122607 sw: fix preservation of text frame cache entries

tdf#122607 sw: fix preservation of text frame cache entries

SwSaveSetLRUOfst would leave only 50 cache entries available for the
CalcLayout() to use; apparently it's not enough for this document.

The difference between the 1st loading/layout and the 3rd loading/layout
of the document is that in many paragraphs the cache entry is missing,
because the entires of the previous loads were clogging up the cache
and were preserved here, and the cache only has 50 available entries;
if enough entries are available, everything is positioned properly.

The idea with the 100 entries per visible shell actually comes from the
CVS initial import, where there was a comment suggesting that; but the
corresponding parameter was actually unused and removed in
7c704c78d3c652504c064b4ac7af55a2c1ee49bb.

Ideally we'd have time to investigate why a missing cache entry causes
the wrong position...

Change-Id: I64a72a94361dbf5717bbc709fa3bc9abbe18a37c
Reviewed-on: https://gerrit.libreoffice.org/71542
Tested-by: Jenkins
Reviewed-by: Michael Stahl <Michael.Stahl@cib.de>