largefiles: add tests for summary/outgoing improved in subsequent patches This patch adds tests for summary/outgoing improved in subsequent patches, to reduce amount of diffs in each patches. This patch adds new revisions below: - revision #2 adds new largefiles, but they contain as same data as one already existing this causes that multiple standins refer the same data entity - revision #3, #4 and #5 change the already existing largefile this causes that multiple data entities are outgoing for the standin. #5 can be used to check de-duplication of "(hash, filename)" pair.