testsuite: core_backtrace dupe test

Problems with no matching executable are never dupes.

Related to rhbz#1105316

Signed-off-by: Jakub Filak <jfilak@redhat.com>
local duplicates must have matching executables

Closes rhbz#1105316

Signed-off-by: Jakub Filak <jfilak@redhat.com>
Merge branch 'rhbz1105316_local_dupes'