[486923,488941] Fix Stack Overflow in ThreeWayComparisonGroupProvider

When conflicts contain diffs which are refined by containment reference
changes located in a match above a Stackoverflow exception can occur.
This is now avoided.

Bug: 486923
Bug: 488941
Change-Id: I1e6e4b465450baf07c8141d1580cf854bcd02783
Signed-off-by: Simon Delisle <simon.delisle@ericsson.com>
Signed-off-by: Edgar Mueller <emueller@eclipsesource.com>
Signed-off-by: Stefan Dirix <sdirix@eclipsesource.com>
Signed-off-by: Alexandra Buzila <abuzila@eclipsesource.com>
Signed-off-by: Philip Langer <planger@eclipsesource.com>
Also-by: Alexandra Buzila <abuzila@eclipsesource.com>
Also-by: Simon Delisle <simon.delisle@ericsson.com>
7 files changed