New git-rebase backend: no way to drop already-empty commits

[Sami Boukortt <sami@xxxxxxxxxxxx>]

Hi,

Using git 2.26.0, I just tried using `git rebase` to strip empty
commits from a branch, but it leaves them as-is, even with
`--empty=drop`. With the “apply” backend, it removes them properly. Am
I holding it wrong?

`git rebase -i` also doesn’t pre-comment them like it used to.

Thanks.

Best,
Sami