Changes

ci(tidb): improve ddlv1 unit test diagnostics (#4585)

### What changed
- Capture `bazel_coverage_test_ddlargsv1` output into `bazel-test.log`.
- Add the same test result archive/report flow used by the regular unit
test job:
  - archive Bazel JUnit XML
  - archive `bazel-test.log`
  - run `analyze-go-test-from-bazel-output.sh`
  - send test case run report
  - archive `bazel-*.log` and `bazel-*.json`

### Why
To improve diagnostics when Bazel reports timeout/failure summaries,
because the job did not archive and parse test output like the regular
unit test job. This change aligns the diagnostics path and removes the
workspace size difference.

### Replay Test Passed
-
https://prow.tidb.net/jenkins/job/pingcap/job/tidb/job/release-8.5/job/pull_unit_test_ddlv1/270/

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Signed-off-by: lyb <yebin.li@pingcap.com>
 (commit: d1d0ce4)