Output split information for imgdiff when handling large apks

Add a mandatory option in imgdiff to write the split info (i.e.
patch_size, tgt_size, src_ranges) to file when handling large apks.
Therefore, the caller of imgdiff can create split transfers based on
the info.

Bug: 63542719
Test: unit tests pass
Change-Id: I853d55d1f999fd576474faa81077f7307f4d856d