Segmentation fault on iOS CI testbed

[freakboy3742]

Describe the bug

We've recently been seeing CI failures on iOS (e.g., this CI run). The problem manifests as a segfault in the iOS simulator just after an error in the tests/widgets/test_webview.py::test_evaluate_javascript test.

How to reproduce the bug

Difficult to reproduce; we're seeing it intermittently in CI - maybe 1 in 10 runs?

Minimum example code

Run the testbed app in CI.

Screenshots

No response

Environment details

• Operating system and version: iOS 18.6
• Python version: 3.12
• Software versions:
  • Briefcase: 0.4.5+
  • Toga: 0.5.4+
  • ...

Logs

...
tests/widgets/test_webview.py::test_static_large_content
PASSED          [ 91%]

tests/widgets/test_webview.py::test_user_agent
PASSED                    [ 91%]

tests/widgets/test_webview.py::test_evaluate_javascript
ERROR            [ 91%]
Child process terminated with signal 15: Terminated

Test suite didn't report a result.
Saving log... started

Log saved to /Users/runner/work/toga/toga/testbed/logs/briefcase.2026_06_28-14_33_25.run.log

Saving log... done
Error: Process completed with exit code 200.

There's no additional context in the Briefcase log - it's a segfault.

Additional context

• The problem test usually passes on a re-run
• The problem test uses the flaky decorator, so the problem could be related to cleanup (and maybe async cleanup of the widget as part of the flaky operation?)
• The next test to execute is another flaky webview test (test_evaluate_javascript_no_handler).