This will make it easier to add more formats without exploding the
common --xxx space and checking a large set of boolean flags.
Also fill out the test coverage while we're here.
Bug: b/412725063
Change-Id: I754013dc6cb3445f8a0979cefec599d55dafdcff
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/471941
Reviewed-by: Gavin Mak <gavinmak@google.com>
Commit-Queue: Mike Frysinger <vapier@google.com>
Tested-by: Mike Frysinger <vapier@google.com>
