The [internal test failure](https://github.com/flutter/flutter/pull/144207#issuecomment-1968236339) was caused by `Focus.withExternalFocusNode` modifying the external node's attributes. The extra changes are in this commit:  https://github.com/flutter/flutter/commit/e53d98b06c6e2ae65271681c4b40b28b2d02ad04

CL with (almost) passing TGP: cl/611157582