Migrate runnable and e2e scripts onto shared Python tooling helpers

[doublemover]

Parent inventory: #8108
Blocked by: #8119, #8120, #8121, #8122

Objective

Migrate runnable/e2e checker scripts to shared Python helpers after the helper modules are available.

Shared Module Specification

• Migrate runnable block ARC, error, object model, storage reflection, concurrency, interop, metaprogramming, release candidate, bootstrap, showcase, stdlib, performance, platform-hardening, package-ecosystem, and application-architecture families as applicable.
• Use shared path, JSON, subprocess, public workflow output, probe output, and probe compile helpers.
• Keep domain-specific assertions local.
• Preserve public command behavior and report paths.

Migration Checklist

• Migrate scripts in clusters that share the same output parser shape.
• Run focused validation after each cluster.
• Remove now-unused local helper definitions after each script passes.
• Document intentionally local helpers left behind because semantics differ.

Inventory

• Replacement scope is every matching helper occurrence from the Python inventories in the path/JSON, subprocess, output-parser, and probe-compile issues that lives in scripts/check_objc3c_runnable_*, scripts/check_objc3c_*_integration.py, or scripts/objc3c_public_workflow_runner.py.
• High-risk files: runnable block ARC, concurrency, error, interop, metaprogramming, object model, release candidate, storage reflection, and scripts/objc3c_public_workflow_runner.py.

Performance And Reliability Requirements

• Keep helper code small, dependency-light, and fast enough for normal development feedback.
• Add focused tests for edge cases before broad migration.
• Preserve existing output schemas and public behavior unless an intentional bug fix is validated.
• Keep production helpers separated from test-only helpers.
• Do not use tmp/ as durable source-of-truth; generated temporary files are allowed only as transient command inputs.

Fast Tests

• Run python -m py_compile for every changed runnable/e2e script.
• Run each affected checker directly or through its npm script.
• Run representative public workflow runner commands that emit report paths.
• Run final affected runnable suites once all clusters are migrated.

End-To-End Completion Criteria

• Runnable/e2e scripts no longer carry duplicated generic helpers when shared semantics exist.
• Public report path extraction and probe parsing behavior is shared.
• No script becomes slower from helper import overhead in normal execution.