Implement `computeDryBaseline` for cupertino `RenderBox`es

[LongCatIsLooong]

The _debugVerifyDryBaselines method verifies that dry baseline implementation is consistent with the wet baseline method at the current constraints.

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.
• [ ] I followed the breaking change policy and added Data Driven Fixes where supported.
• [ ] All existing and new tests are passing.

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[auto-submit[bot]]

auto label is removed for flutter/flutter/145951, due to - The status or check suite Windows build_tests_2_7 has failed. Please fix the issues identified (or deflake) before re-applying this label.