This is a combination of 2 commits.

Flatten ScRangeList::Join() recursion

Joining an existing list of identical ranges could end up in a
very deep (but not infinite) recursion which could lead to stack
exhaustion. Recursion is unnecessary if we re-enter the loop with
the picked range. Continuing the loop as it was done after
recursion isn't necessary either, to the contrary, as long as
there is one join try the entire list again.

Commit f6eefd96 pointed this out
as the UBSan build runs with ulimit -s 8192

Reviewed-on: https://gerrit.libreoffice.org/48360Reviewed-by: Eike Rathke <erack@redhat.com>
Tested-by: Jenkins <ci@libreoffice.org>
(cherry picked from commit 03f42966)

Flatten ScRangePairList::Join() recursion

Similar to ScRangeList::Join() done before.

Reviewed-on: https://gerrit.libreoffice.org/48361Reviewed-by: Eike Rathke <erack@redhat.com>
Tested-by: Jenkins <ci@libreoffice.org>
(cherry picked from commit 73049e5d)

e513b4c72bc211c196e13761b63446174321a389

 Conflicts:
	sc/source/core/tool/rangelst.cxx

Backported.

Change-Id: Ibbc542fc8ae6d1509744aa731771eb6e32a38841
Reviewed-on: https://gerrit.libreoffice.org/48411Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>