Dependent pull requests: inacurrate bot comment

[Roland Westrelin]

I have this dependent pull request:

https://github.com/openjdk/jdk11u-dev/pull/1049

I already integrated the PR that it depended on. The bot added this
message as a result:

https://github.com/openjdk/jdk11u-dev/pull/1049#issuecomment-1112959031

It says:

git checkout backport-8280799

which is the branch of the already integrated PR. Shouldn't it be:

git checkout backport-8281811

that is the branch of PR#1049 that needs to be updated?

Roland.