dex2oat: Show memory usage values in bytes

Memory usage values are rounded down to an integer and shown in the
unit that would be most appropriate (refer to art::PrettySize());
e.g. if the value is at least 1 MB, but less than 1 GB, then it will
be shown in MB. However, that can introduce a very large error; for
example, a value that is close to, but less than 2 MB, will be
displayed as 1 MB.

This change forces dex2oat to print the raw value in bytes as well,
which may make memory usage analysis more accurate.

Change-Id: Id86a9fe21e8af0f02e77fac21cad51d35d941294