[CI] Flaky: Mac Catalyst NativeAOT exits 133 in CGImageMetadataTest

## Flaky Test Report

**Signature:** `maccatalyst-nativeaot-cgimagemetadata-exit-133`
**Test/configuration:** `monotouch-test/Mac Catalyst/Release (trimmable static registrar, NativeAOT)` while entering `MonoTouchFixtures.CoreGraphics.CGImageMetadataTest`
**Classification:** Genuinely flaky test
**First observed:** 2026-07-21 12:22 UTC
**Latest observed:** 2026-08-03 14:27 UTC

### Occurrences

| PR / head | Azure run / attempt | Job | Outcome |
|---|---|---|---|
| #26180 / `897e85a4b8e8e206c57ea59a7b0c3088abf18e15` | [14718322 / 1](https://devdiv.visualstudio.com/DevDiv/_build/results?buildId=14718322) | `T: monotouch_maccatalyst` (`73408371-a55e-5ff5-5372-c49d56cfe7c2`) | The NativeAOT process exited 133 while entering `CGImageMetadataTest`. The same head/configuration had passed in [14716050](https://devdiv.visualstudio.com/DevDiv/_build/results?buildId=14716050), and failed-job retry attempt 2 cleared this crash; unrelated jobs kept the overall run failed. |
| #26379 / `d97396de11660c46503461cc61cc6aadc1c56dd4` | [14850072 / 1](https://devdiv.visualstudio.com/DevDiv/_build/results?buildId=14850072) | [`T: monotouch_maccatalyst` / `Run tests`](https://devdiv.visualstudio.com/DevDiv/_build/results?buildId=14850072&view=logs&j=73408371-a55e-5ff5-5372-c49d56cfe7c2&t=6461d47d-e6ea-5999-dbbe-6992de98f697), `AcesShared 37` | The same configuration exited 133 at `CGImageMetadataTest`; no crash report was produced. |

**Total:** 2 confirmed occurrences across 2 distinct PRs.

### Current diagnostic lines

```text
MonoTouchFixtures.CoreGraphics.CGImageMetadataTest
Process monotouchtest exited with 133
Test run crashed (exit code: 133).
No crash reports
```

In run 14850072, the neighboring `Release (NativeAOT)` and `Release (NativeAOT, .NET 11 defaults)` configurations passed. This isolates the recurrence to the trimmable-static-registrar NativeAOT variation rather than a general NativeAOT build failure.

### Impact and retry status

The crash fails the Mac Catalyst test job without an NUnit failure or native crash report. No retry was submitted for #26379 because the same run also has seven deterministic `No valid ... code signing keys found in keychain` failures; rerunning failed jobs would repeat those failures until the signing bundle is independently validated.

### Investigation

- Parsed the TestSummary and HtmlReport execution log for run 14850072.
- Confirmed the stable test/configuration/exit-code signature against the retained #26180 occurrence.
- Searched all open and closed issues by exact test name, process exit text, configuration, and CoreGraphics component. #25171, #25687, #25860, and #26221 describe different crash or timeout roots.
- Azure DevOps no longer returns builds 14718322 or 14716050 through the API, so their retained artifacts and task IDs are unavailable due to artifact retention.

### Workaround

Retry the failed Mac Catalyst job only when the same run has no deterministic co-failures and retry accounting permits it. No source workaround is known.

---
Generated from recurring cross-PR CI monitoring evidence.

Start with MonoTouchFixtures.CoreGraphics.CGImageMetadataTest in the Mac Catalyst Release trimmable-static-registrar NativeAOT configuration, then compare the retained logs for runs 14718322 and 14850072 with the neighboring passing configurations. Check the test-entry logs and retry behavior; done means identifying an actionable cause or fix for exit 133 without relying on a blind retry.

Written by the indexing model from the issue text.