Commit 212ec9a29a / feature #14121 already ordered partitions by
decreasing size, however it was common in samples/userspace/shared_mem/
/sample.kernel.memory_protection.shared_mem for two partitions to have
the same size and be randomly ordered between them. This adds the
partition name as a second sort key.
Unlike previous attempt in commit 725abdf430 this doesn't use the
partition name as the first (and only) key and doesn't break the
decreasing size order. Huge thanks to Sigvart Hovland for spotting this
in a post-merge but prompt code review.
Signed-off-by: Marc Herbert <marc.herbert@intel.com>