Sort .git-blame-ignore-revs by commit order

[brooks]

Summary

This makes it easier to add blocks of commits such as
4ca5df80393e1f2..c90d0600ee000e78 which do a single thing over the
course of multiple commits. Sorting by hash would require manually
inserting each one with a comment.

[emaste]

I think this is a sensible change but the comment should indicate if it is sorted newest or oldest first.

[emaste]

can probably roll the comment change from D42602 in

[brooks]

• Update sort order comment in the correct commit