Make FunctionType.typedefType final
Make FunctionType.typedefType final

Change-Id: I52ec7cdd20d431a324634a6caf0e6f1e9178c8c8
Reviewed-on: https://dart-review.googlesource.com/c/82203
Auto-Submit: Peter von der Ahé <ad40f903ca639ca334d95dc5a5f0ae92bd708079@google.com>
Reviewed-by: Kevin Millikin <a6737c91ef81c790d8ad0ae8762bd5b2332a6e42@google.com>
Reviewed-by: Dmitry Stefantsov <95a4b7e39916a54bd6477bec6a6de014b977db32@google.com>
Commit-Queue: Dmitry Stefantsov <95a4b7e39916a54bd6477bec6a6de014b977db32@google.com>

dart-lang/sdk,dartino/dart-sdk,dart-lang/sdk,dartino/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dart-lang/sdk,dart-archive/dart-sdk,dart-lang/sdk,dart-archive/dart-sdk,dartino/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dartino/dart-sdk,dart-lang/sdk,dart-archive/dart-sdk,dartino/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk,dart-archive/dart-sdk