[ci-scan] Helix work items exit 1 despite all tests passing on osx-x64 (coreclr outerloop, interpreter)

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> Review the [workflow run logs](https://github.com/dotnet/runtime/actions/runs/25835993942) for details.
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**Summary:**
Multiple Helix work items in coreclr outerloop and interpreter pipelines fail with `exit 1` despite all individual tests passing (Exit Code: 100, test_exit_code=0, xunitlogchecker_exit_code=0, result_exit_code=0).

**Failed in (4+):**
- [runtime-coreclr outerloop 1419461](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1419461) — HardwareIntrinsics_X86_ro, baseservices-exceptions, Regression_PdbOnly_r, jit64_4
- [runtime-interpreter 1419028](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1419028) — profiler, GC-simulator, HardwareIntrinsics_X86_ro, JIT_others, JIT.Generics, Regression_ro_2

**Console Log:** [baseservices-exceptions](https://helix.dot.net/api/2019-06-17/jobs/bc3787a8-9f24-4141-8de2-cb76b34b2f6a/workitems/baseservices-exceptions/console)

**Error pattern (end of every affected work item log):**
```
Test Harness Exitcode is : 0
Exit Code: 100
+ test_exit_code=0
+ xunitlogchecker_exit_code=0
+ result_exit_code=0
+ export _commandExitCode=0
+ _commandExitCode=0
+ exit 1
['' END OF WORK ITEM LOG: Command exited with 1]
```

All tests pass individually (Exit Code 100 = pass for coreclr tests), yet the wrapper shell script exits with 1 after setting `_commandExitCode=0`.

**Impact on platforms:**
- runtime-coreclr outerloop (def 108) · osx-x64 · OSX.15.Amd64.Open · multiple work items
- runtime-interpreter (def 316) · osx-x64 · OSX.15.Amd64.Open · multiple work items
- Potentially runtime-coreclr r2r (def 120) and others using the same runner script on macOS

**First build it occurred:** Present in builds from 2026-05-13 and 2026-05-14. This is within the scanned window and may not be the true origin.

**Recommended action:**
1. Investigate the Helix wrapper script (likely `runpaltestshelix.sh` or the generic coreclr test runner for Helix) to find why it exits 1 when all sub-test exit codes are 0.
2. The issue appears to be macOS-specific (OSX.15.Amd64.Open queue). Check for recent changes to the Helix runner scripts or the OSX.15 queue configuration.
3. Assign to area-Infrastructure or the test-infra team for investigation.

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> [!NOTE]
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> 🔒 Integrity filter blocked 1 item
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> The following item was blocked because it doesn't meet the GitHub integrity level.
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> - [#125825](https://github.com/dotnet/runtime/issues/125825) `search_issues`: has lower integrity than agent requires. The agent cannot read data with integrity below "approved".
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> To allow these resources, lower `min-integrity` in your GitHub frontmatter:
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> Generated by [CI Outer-Loop Failure Scanner](https://github.com/dotnet/runtime/actions/runs/25835993942/agentic_workflow) · ● 39.1M · [◷](https://github.com/search?q=repo%3Adotnet%2Fruntime+is%3Aissue+%22gh-aw-workflow-call-id%3A+dotnet%2Fruntime%2Fci-failure-scan%22&type=issues)