At some point we are likely to use stabilization branches in the mainline jdk repo rather than a separate repo. We should exclude branches matching "jdk*" like we currently do for "master" and "pr/*".

A potential drawback of doing this is that it will exclude developer branches named jdk-8888888 or similar, using a lower-case "jdk". Developers who want a GHA run will need to use "JDK" (uppercase) or some other prefix.

I suspect that this will not be a problem in practice. I checked the most recent 100 open pull requests in the jdk project, and while many of them use "JDK" (upper case) as a prefix, I found none that use "jdk" (lower case).