iOS apps can be ad-hoc codesigned (signed without a developer cert, and instead with identity -), which allows them to run on simulators, but not real devices. We use ad-hoc codesigning for host-only simulator tests on machines where the developer cert is not set up:

When the Flutter.framework is codesigned (every channel but master), the app will crash on launch because the framework is codesigned differently (not ad-hoc) than the app. This manifests in dev/beta/release cherry-pick tests because the framework is codesigned, but not on master.
Instead of skipped codesigning the framework in this case, instead ad-hoc codesign with identity -.

Fixes #93517

Pre-launch Checklist

• I read the Contributor Guide and followed the process outlined there for submitting PRs.
• I read the Tree Hygiene wiki page, which explains my responsibilities.
• I read and followed the Flutter Style Guide, including Features we expect every widget to implement.
• I signed the CLA.
• I listed at least one issue that this PR fixes in the description above.
• I updated/added relevant documentation (doc comments with ///).
• I added new tests to check the change I am making, or this PR is test-exempt.
• All existing and new tests are passing.

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