tests: show pytest xfail/xpass results in analyze.py

[donaldsharp]

Topotests now use pytest.mark.xfail, which the pytest framework records as skips (expected fail) or failures (strict unexpected pass). Let's teach analyze.py to classify those separately, include known failures in the default listing, and print aligned output to make it more pleasing to the eye.

Old output:

analyze.py -Ar run_save
bgp_batch_clearing/test_bgp_batch_clearing.py::test_link_down_clears_routes

New output shows this:

analyze.py -Ar run_save
0: Known Failure : bgp_rfc7606_treat_as_withdraw/test_bgp_rfc7606_treat_as_withdraw.py::test_treat_as_withdraw[ibgp-aspath-as-zero]
1: Failure : bgp_batch_clearing/test_bgp_batch_clearing.py::test_link_down_clears_routes

[greptile-apps]

Greptile Summary

This PR extends topotest JUnit analysis to distinguish expected failures and strict unexpected passes, includes known failures by default, and aligns status output.

• Adds reusable testcase outcome classifiers and XML-node helpers.
• Splits XFAIL and XPASS counts from aggregate skip and failure totals.
• Adds XFAIL/XPASS selection letters and status labels.
• Changes ordinary listing output to include ordinals, which breaks existing CI parsing.

Confidence Score: 4/5

This PR should not merge until the default listing preserves testcase names in the field consumed by the CI rerun workflow.

The new unconditional ordinal prefix causes existing cut -f1 -d: consumers to pass numeric ordinals rather than testcase paths to pytest.

Files Needing Attention: tests/topotests/analyze.py

Important Files Changed

Filename	Overview
tests/topotests/analyze.py	Adds XFAIL/XPASS classification and formatting, but the merged listing branch breaks CI consumers by prefixing default output with ordinals.

Prompt To Fix All With AI

### Issue 1
tests/topotests/analyze.py:524-529
**Ordinal prefix breaks CI reruns**

When CI invokes `analyze.py` without `--enumerate`, this merged branch places an ordinal before the first colon. The existing `cut -f1 -d:` consumers therefore pass numbers such as `0` instead of testcase paths to pytest, preventing the selected tests from being rerun.

---

For each issue above, determine whether it is valid and should be fixed. If so, fix it directly.

_{Reviews (1): Last reviewed commit: "tests: show pytest xfail/xpass results i..." | Re-trigger Greptile}

[greptile-apps]

Ordinal prefix breaks CI reruns

When CI invokes analyze.py without --enumerate, this merged branch places an ordinal before the first colon. The existing cut -f1 -d: consumers therefore pass numbers such as 0 instead of testcase paths to pytest, preventing the selected tests from being rerun.

Prompt To Fix With AI

This is a comment left during a code review.
Path: tests/topotests/analyze.py
Line: 524-529

Comment:
**Ordinal prefix breaks CI reruns**

When CI invokes `analyze.py` without `--enumerate`, this merged branch places an ordinal before the first colon. The existing `cut -f1 -d:` consumers therefore pass numbers such as `0` instead of testcase paths to pytest, preventing the selected tests from being rerun.

---

For each issue above, determine whether it is valid and should be fixed. If so, fix it directly.

[riw777]

Looks good.