[GR-60823] Do not run GraalVM gate on master branch.

[graalvmbot]

Currently, the GraalVM gate runs on every push of a PR, and whenever we push the master and release branches. Since all changes to the master branch are proposed through PRs, all PRs are at least tested twice: on every push (last commit of PR merged into master) and after merge (merge commit created by our merge bot).

This PR removes this duplication to reduce the use of CI resources.

[zakkak]

@fniephaus one thing to keep in mind is that when testing a PR, the base branch commit hash (master or release/* in this case) might not be the same as when you actually merge the PR. I.e. more changes might have been merged between the CI run and the actual merge.

[fniephaus]

@zakkak do you think this is an issue in practice?

[zakkak]

@zakkak do you think this is an issue in practice?

It depends on how important it is to ensure that master is never broken.

If you are OK with having master broken for a short period of time, since the breakage will probably be noticed in the first couple of PRs that will be submitted after the breaking merge, then it's an acceptable compromise.

A major drawback is that while master is broken people working on it might spend time trying to understand what they are doing wrong although the error won't be on their side.

In general, I personally don't expect such issues to pop up often and am personally OK with the change, just wanted to make clear that this change might result in master getting broken despite the CI being green in the PRs.

[fniephaus]

A major drawback is that while master is broken people working on it might spend time trying to understand what they are doing wrong although the error won't be on their side.

Right, this shouldn't happen at all because we still run our internal gates but if it happens in practice, we can add master builds again.

In general, I personally don't expect such issues to pop up often and am personally OK with the change, just wanted to make clear that this change might result in master getting broken despite the CI being green in the PRs.

Good, and please let us know if you ever see something like this happening.