Compare list only and ignore SHA-1 with option -l

Current image diff tool compares SHA-1, so it generates more output
when only file list comparison is required. This change adds an extra
option -l to compare file list only if needed.

Bug: 144398762
Test: Tested locally with two artifacts
Change-Id: I47351fc19fb8089c65ed3d3ba901dfe83aa7deba
1 file changed