Remove broken GitHub action status badges
Remove broken GitHub action status badges

GitHub actions have a [bug](https://github.community/t5/GitHub-Actions/Actions-Reporting-Wrong-Branch-on-Merges/td-p/36966) where workflow runs are tagged with the branch that a merge came from. This breaks the status badge and makes it unusable because it can only be for a single branch. I also changed the link to point at all runs with the "push" event, since it breaks that search as well. Right now, this contains pushes to the ci-test branch, but we can remove this trigger. CMake already runs on all PRs and we can make Bazel run on PRs from ci-test.

Closes #395

COPYBARA_INTEGRATE_REVIEW=https://github.com/google/iree/pull/395 from google:ga-status-badge 13136cd2f32a63c79d3299a3508c71700c3f46eb
PiperOrigin-RevId: 288380520

iree-org/iree,google/iree,iree-org/iree,google/iree,google/iree,iree-org/iree,google/iree,iree-org/iree,google/iree,iree-org/iree,iree-org/iree,google/iree,iree-org/iree,google/iree