Retry RNTester build after Apple clang frontend crash

[cortinico]

Summary:

The default-branch Test All run for commit 9b7c956c356f0257adf453ff5791b6508f5ab869 hit an Apple clang frontend crash while compiling RNTMyNativeViewComponentView.mm with Xcode 16.4:

• clang: error: unable to execute command: Segmentation fault: 11
• clang: error: clang frontend command failed due to signal

That build never uploaded RNTesterApp-NewArch-Debug, so the downstream Debug E2E check also failed while downloading the missing artifact. The parent commit and the preceding 14 sampled test_ios_rntester (Debug, false) jobs passed, including the same compiler invocation on the parent SHA. The only commit in the chronological range (cca720709a74c797f30df9e6a96832fabc88c8d5..9b7c956c356f0257adf453ff5791b6508f5ab869) changes Android test-helper names and comments/documentation; it does not change the failing Objective-C++ source. This makes a hosted compiler crash much more likely than a deterministic source regression, although a local Xcode 16.4 reproduction was not available.

This change retries the RNTester build once only when both observed Apple clang crash signatures are present. It removes DerivedData before retrying. Other build failures are not retried, and a repeated clang crash still fails the job.

Failure: https://github.com/react/react-native/actions/runs/38760856731/job/116533978498

Dependent missing-artifact failure: https://github.com/react/react-native/actions/runs/38760856731/job/116538539515

Risk / limitations: The retry is intentionally limited to this exact compiler-crash signature and one additional attempt. It does not address the underlying Apple clang defect. Full RNTester reproduction was not practical locally because the available machine has Xcode 26.6 rather than the hosted Xcode 16.4 environment.

Changelog:

[INTERNAL] [FIXED] - Retry the RNTester iOS build once when Apple clang itself crashes.

Test Plan:

• git diff --check — passed.
• Parsed .github/actions/test-ios-rntester/action.yml with Ruby's YAML parser — passed.
• Extracted and exercised the modified Build RNTester shell block with a fake xcodebuild in four scenarios:
  • first attempt succeeds: 1 invocation, success;
  • matching compiler crash then success: 2 invocations, success;
  • matching compiler crash twice: 2 invocations, failure;
  • unrelated deterministic compile error: 1 invocation, failure.
• Did not run the full RNTester iOS build locally; the available Xcode version does not match CI's Xcode 16.4.