Test config changes on main can cause problems for cherry picks to beta and stable #51481
Description
This is a tracking issue for potential problems from the test/builder configuration changes we are making for dart2js and ddc.
- Test and builder configurations are defined in the SDK repo:
https://github.com/dart-lang/sdk/blob/main/tools/bots/test_matrix.json - The infra that runs the builders is configured outside of the SDK and is independent of the SDK main/beta/stable branches.
- When we make a change that requires changes on both sides they are unlikely to be backwards compatible.
Cherry picks for any other reason that happen after the configuration change lands in the SDK and before it gets merged into the cherry pick destination branch will not be able to run tests with the ddc or dart2js builders.
In that event, we should also cherry pick the configuration changes that landed in the SDK.
cc @athomas