Summary

Moves the hardcoded imageUploadMap and imagePullMap Groovy maps out of openjdk_tests
and into external JSON config files, completing the second phase of the Portable Container
Testing setup described in #6188.
Closes #6188
Related: automation/issues/294

Background

PR #6195 ("Set up pipeline for criu and portable SCC") added inline Groovy maps for both
CRIU and portable SCC directly into openjdk_tests. During review, it was acknowledged
that this mapping would eventually move to a separate config file to make the pipeline
extensible without requiring code changes.
This PR implements that config-folder approach.

Changes

New: buildenv/jenkins/config/portable-container/

config/portable-container/
├── README.md
├── criu/
│   ├── imageUploadMap.json   # machine combinations for CRIU image upload
│   └── imagePullMap.json     # machine combinations for CRIU image pull/restore
└── scc/
    ├── imageUploadMap.json   # machine combinations for SCC image upload
    └── imagePullMap.json     # machine combinations for SCC image pull/restore

Each imageUploadMap.json carries:

• commonLabelBase — base Jenkins node label for the feature
• buildList — BUILD_LIST value for child jobs
• target — TARGET value for upload child jobs
• excludeTargetOnPlatform — platform-specific test exclusions (e.g. CRIU ppc64le backlog/1099)
• platforms — map of platform → list of label suffixes

Each imagePullMap.json carries:

• commonLabelBase
• platforms

Modified: buildenv/jenkins/openjdk_tests

• Replaces all hardcoded Groovy imageUploadMap/imagePullMap blocks with a
  node { checkout scm; readJSON(...) } config-loading block (same pattern as
  aqaTestPipeline.groovy).
• Uses findFiles(glob: ".../portable-container/*/imageUploadMap.json") for
  auto-discovery — the pipeline detects supported features from the directory
  structure at runtime.
• All orchestration logic (generateJobViaAutoGen, parallel, build job:,
  changeParam) is unchanged.
• CRIU JDK26+ skip and ppc64le target exclusion are fully preserved.

Net result: −104 / +63 lines in openjdk_tests.

How to Add a New Feature (after this PR)

1. Implement tests in aqa-tests/external/<feature>/
2. Create buildenv/jenkins/config/portable-container/<feature>/imageUploadMap.json
3. Create buildenv/jenkins/config/portable-container/<feature>/imagePullMap.json

No changes to openjdk_tests required.

Testing

• All 4 JSON files validated as syntactically correct JSON.
• Logic simulation confirms the Groovy maps constructed from JSON are
  identical to the previous hardcoded maps for all platforms (CRIU: 15 upload
  • 14 pull entries; SCC: 4 upload + 4 pull entries).
• CRIU target string, ppc64le exclusion substring, and resulting target-after-exclusion
  all verified to match the original values exactly.