[stable] Add errors for base transitivity and base/final implements of a core lib declaration through a 2.19 library and a 3.0 library. Cherry pick for the following behaviour from 3 different CLs. Error produced when a post-feature library implements a pre-feature library declaration that has a final/base core library class as a super declaration. Error produced when a post-feature library subtypes (but not implements) a pre-feature library declaration that has a final/base core library class as a super declaration. Fixes: https://github.com/dart-lang/sdk/issues/52406 Bug: https://github.com/dart-lang/sdk/issues/52315, https://github.com/dart-lang/sdk/issues/52115, https://github.com/dart-lang/sdk/issues/52078 Cherry-pick: https://dart-review.googlesource.com/c/sdk/+/302365 Cherry-pick: https://dart-review.googlesource.com/c/sdk/+/301503 Cherry-pick: https://dart-review.googlesource.com/c/sdk/+/300861 Cherry-pick: https://dart-review.googlesource.com/c/sdk/+/301442 Cherry-pick: https://dart-review.googlesource.com/c/sdk/+/300880 Change-Id: I2a192a157d417c1de7656aa624d3b10d9e67626e Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/302851 Commit-Queue: Kallen Tu <kallentu@google.com> Reviewed-by: Konstantin Shcheglov <scheglov@google.com> Reviewed-by: Johnni Winther <johnniwinther@google.com>
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