Changes

chore(pipeline) migrate tidb pull unit test and pull integration test to GCP (#4374)

## Summary

This PR migrates `pingcap-inc` CI jobs (with focus on
`tidb/release-8.5`) to the GCP execution path and aligns pipeline
behavior with the new infra dependencies (GCS/GAR-based flow), while
updating shared CI helpers used by these jobs.

## Scope

- Introduce `pingcap-inc` presubmit job definitions and job entrypoints.
- Add/migrate `pingcap-inc/tidb/release-8.5` pipelines and pod specs to
GCP-ready configs.
- Update shared pipeline library behavior for coverage upload and common
CI runtime compatibility.
- Keep temporary Bazel deps URL hotfix logic in CI layer for replay/job
stability before upstream tidb repo cleanup is fully landed.
 (commit: 6ffee21)