[CI] iOS 27 simulator launch intermittently returns HE0042 with no process handle

## Failure signature

An iOS 27 simulator boots and the app installs successfully, but `simctl launch` then returns NSPOSIX error 3 without a process handle:

```text
Simulator device failed to launch .
Application launch for '' did not return a process handle nor launch error.
No such process
error HE0042: Could not launch the app ... simctl returned exit code 3
```

The harness classifies the configuration as `LaunchFailure`; no test assertion runs.

## Confirmed occurrences

| PR / head | Azure run, job, and configuration | Worker |
|---|---|---|
| #26504 / `a41bc2537248a8a21a9095e59fce1419b14b6888` | [15159098 attempt 1 — `linker_ios` / `link all` / iOS simulator Debug](https://dev.azure.com/devdiv/DevDiv/_build/results?buildId=15159098&view=logs&j=3f6ef66d-5190-5708-a885-35d26e0e0d89&t=b9f07791-45f9-584d-6ecc-bf5dae611e17) | `AcesShared 22` |
| #26514 / `18a39779782fb35e5ae7a7ad5bf779a023c59e00` | [15168255 attempt 1 — `introspection` / iOS 27 simulator Debug](https://dev.azure.com/devdiv/DevDiv/_build/results?buildId=15168255&view=logs&j=6e00b7cd-b8a5-532f-afa5-bfd80bdfa50e&t=a81f29a9-241f-5e78-595f-ca2207a47c04) | `AcesShared 52` |

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

First observed failure: `2026-08-31T23:37:40Z`. Latest observed failure: `2026-09-01T15:14:33Z`.

## Classification

**Genuinely flaky CoreSimulator launch failure.** Evidence:

- The same normalized launch error occurs in unrelated test suites and PRs.
- Both apps build and install before `simctl launch` fails.
- #26504's unchanged failed-job retry passed on `AcesShared 1`, and build 15159098 completed successfully.
- On #26514, the other five introspection configurations pass, including iOS 16, tvOS 27, tvOS 16, macOS, and Mac Catalyst.
- The #26514 artifact contains a contemporaneous `tccd` crash, but no crash of the test app and no deterministic assertion failure.

## Investigation performed

- Inspected Azure timelines and `Run tests` task logs for both builds.
- Downloaded and inspected #26514's TestSummary and full HTML/xharness report.
- Verified successful simulator boot, app installation, and the exact failing `simctl launch` invocation.
- Searched all open and closed issues separately by `HE0042`, `simctl returned exit code 3`, `did not return a process handle`, introspection, and Xcode 27 terms.
- Closed issue #18602 has similar surface text but a different root cause: a user project specified the device RID `ios-arm64` while targeting a simulator. It is not canonical for this CI signature.

## Retry status and workaround

- #26504: external simulator failed-jobs attempt 2 succeeded; retry usage was 1 lifetime / 1 current-head request.
- #26514: build 15168255 remains active, so no retry has been submitted. After terminal status, refresh the head, mergeability, active work, and budgets before rerunning failed simulator jobs.

Retrying the affected simulator job is the current workaround. No source, API binding, or suppression-file change is indicated.

Azure logs and artifacts are retention-limited.

Start with the Azure timelines and Run tests task logs for the affected simulator jobs, then review the TestSummary and full xharness report. Reproduce the `simctl launch` failure and compare a failed job with its retry; done means identifying a reliable fix or confirming that retrying is the only workaround.

Written by the indexing model from the issue text.