Refactor verify codesigned tests in order to reduce testing logic in test.dart and allow for later implementing package:test onto the existing verify codesigned tests
Part of https://github.com/flutter/flutter/issues/145482
On the beta branch:
```
Verifying the code signature of /Users/m/Projects/flutter/bin/cache/artifacts/engine/ios-profile/extension_safe/Flutter.xcframework
Verifying the code signature of /Users/m/Projects/flutter/bin/cache/artifacts/engine/ios-profile/Flutter.xcframework
Verifying the code signature of /Users/m/Projects/flutter/bin/cache/artifacts/engine/ios/extension_safe/Flutter.xcframework
Verifying the code signature of /Users/m/Projects/flutter/bin/cache/artifacts/engine/ios/Flutter.xcframework
Verifying the code signature of /Users/m/Projects/flutter/bin/cache/artifacts/engine/ios-release/extension_safe/Flutter.xcframework
Verifying the code signature of /Users/m/Projects/flutter/bin/cache/artifacts/engine/ios-release/Flutter.xcframework
```
Fixes https://github.com/flutter/flutter/issues/140934