What happened

1. Commit 1ba4f1f lands on master.
2. Cirrus triggers a master branch build of commit 1ba4f1f which eventually goes green.
3. Test branch v0.0.1 gets pushed to flutter/flutter with no new commits and HEAD at 1ba4f1f.
4. Cirrus triggers a v0.0.1 branch build of commit 1ba4f1f, which fails on (among other tests) verify_binaries_codesigned-macos, because this commit was never published to dev and thus never codesigned. Because Flutter macOS engine binaries are not codesigned on master, this does not run if a PR is attempting to merge into master of if a commit is on master. Thus, the test ran on v0.0.1 branch, and failed.
5. The build dashboard queries the cirrus status for commit 1ba4f1f and pulls the status for the v0.0.1 branch build (which failed) rather than the build for master (which passed).

Proposed solutions

1. Until engine binaries are codesigned on master, the verify_binaries_codesigned-macos cirrus test only_if logic should be updated to only run on branches that are expected to be codesigned (@christopherfujino can do this once release branch naming is solidified).
2. The flutter dashboard should not query cirrus jobs based solely on the commit revision hash, but also on the branch.