...instead of removing an arbitrary ScLookupCache with a matching ScRange from
the first ScLookupCacheMap that happens to contain one.

79449d73 "make VLOOKUP in Calc thread-safe"
introduced per-thread ScLookupCacheMaps, so that multiple ScLookupCacheMaps can
contain ScLookupCaches with identical ScRanges.  For example, UITest_calc_tests6
adds ScLookupCaches for ScRange 1!R2C18:R97C18 to different threads'
ScLookupCacheMaps.  That causes confusion so that calling
ScDocument::RemoveLookupCacheHelper to remove an ScLookupCache from a
mismatching ScLookupCacheMap accesses a different

  ScLookupCache* pCache = (*it).second.release();

that may already have been destroyed; see failing ASan/UBSan builds like
<https://ci.libreoffice.org//job/lo_ubsan/1067/>.

Change-Id: I70c33b236dc502b8a98e0e313d422424eec5dbca
Reviewed-on: https://gerrit.libreoffice.org/62194
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>