classes/buildhistory: ensure eSDK sstate lists sorted secondarily by name

classes/buildhistory: ensure eSDK sstate lists sorted secondarily by name

I got fed up with seeing items dance around in sstate-package-sizes.txt
in the buildhistory git repo simply because they have the same size.
Let's sort the list first by size and then also by name to ensure items
with the same size are deterministically sorted.

Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>