On push builds, CircleCI provides `CIRCLE_COMPARE_URL`, which we use to
extract the commit range for a given build. When a workflow is rerun
(e.g. to recover from a flaked job), `CIRCLE_COMPARE_URL` is not
defined, causing some jobs to fail.
This commit fixes it by retrieving the compare URL from the original
workflow. It uses a slow process involving a (potentially large) number
of requests to CircleCI API.
It depends on the (undocumented) fact, that the `workspace_id` is the
same on all rerun workflows and the same as the original `workflow_id`.
PR Close#27775
Moving the tests over to CircleCI in pretty much "as-is" state just so that we can drop the dependency on Travis.
In the followup changes we plan to migrate these tests to run on sauce under bazel. @gregmagolan is working on that.
I've previously verified that all the tests executed in legacy-unit-tests-local already under bazel.
Therefore the legacy-unit-tests-local job is strictly not necessary any more, but given how flaky legacy-unit-tests-saucelabs is,
it is good to have the -local job just so that we can quickly determine if any failure is a flake or legit issue
(the bazel version of these tests could theoretically run in a slightly different way and fail or not fail in a different way, so having -lcoal job is just an extra safety check).
This change was coauthored with @devversion
PR Close#27937
George Kalpakas
Igor Minar