flowey: vmm_tests: introduce step to verify all tests run on at least one runner

[damanm24]

This PR resolves #2010
With #1991 it is possible (however unlikely) for a contributor to introduce a test that doesn't end up running on any of the vmm_test jobs in CI. This PR introduces a step that verifies the list of all tests built as part of a CI run are run on at least one vmm_test job.

Here are a list of changes that make this possible:

1. Introduce a new flowey node that generates a nextest list command which dumps the tests that are built as part of the nextest archive.
2. Introduce a new flowey node that consumes the output from nextest list and the corresponding junit xml that was produced from all vmm_test runs. This node then gathers a full set of tests from both artifacts and compares them to make sure the sets are equal.
3. Expanded flowey's built-in artifact publishing API to mark artifacts as force publish which means they are still published if a previous step in the job fails.

[Copilot]

Pull Request Overview

This PR introduces infrastructure to verify test coverage by creating a step that parses nextest JUnit XML files to collect test names and ensures all tests run on at least one runner. The implementation adds nextest list command generation, JSON artifact publishing, and a new verification node for comparing test results.

• Adds a new verification step to parse JUnit XML files and extract test names
• Extends nextest integration to generate list commands and publish JSON artifacts
• Updates test result publishing to include nextest list JSON output

Reviewed Changes

Copilot reviewed 12 out of 12 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
flowey/flowey_lib_hvlite/src/_jobs/verify_all_tests_run.rs	New node that parses JUnit XML files to extract test names for verification
flowey/flowey_lib_common/src/run_cargo_nextest_run.rs	Extended to generate nextest list commands and capture JSON output
flowey/flowey_lib_common/src/gen_cargo_nextest_list_cmd.rs	New module for generating cargo nextest list commands
flowey/flowey_lib_common/src/publish_test_results.rs	Updated to publish nextest list JSON as artifacts
.github/workflows/openvmm-pr.yaml	Generated workflow updates reflecting the new artifact publishing
.github/workflows/openvmm-pr-release.yaml	Generated workflow updates reflecting the new artifact publishing

[github-actions]

At least one Petri test failed.

[smalis-msft]

Very cool idea, but I think it needs a bunch of refactoring to clean up the cases where steps have been combined that really should be separate.