Update tests and support negative values in formatBytes().

This updates the tests to match the older commit
f723017481a247b4aa842937c3983b7d7d8f75fd and also adds support for
negative values.

Bug: 23191381
Bug: 11237727
Change-Id: Ib9a1f10031b730ee460658949b388c779cefa041
2 files changed