Enhance the build reproducibility healthcheck scripting to identify pipelines per platform

[adamfarley]

Summary

Currently, we identify the earliest pipeline job that matches a given tag, and assume that is the correct pipeline to use for reproducibility stats across all platforms.

This issue covers the work needed to adopt a per-platform approach, so a user can rerun a build for a specific platform and have the reproducibility stats for that platform be retrieved from the new pipeline job, just as stats for the other platforms are retrieved from another pipeline.

Details

In short, this is a continuation of #1113

Especially Andrew's comment here: https://github.com/adoptium/ci-jenkins-pipelines/pull/1113/files#r1794987902

Additional subtask

When a build is in progress, we get the reproducibility percentages from the in-progress tag (status['upstreamTag']) rather than the previous tag (releaseName). When the former does not contain the latter, we need to get the pipeline build URL and build ID (TRSS) for the latter, and get the reproducibility percentages based on that.