Dynamic interface annotator now automatically annotates classes and
members which are used implicitly:
* Targets of redirecting factories.
* Classes and members used in constants.
* Instance fields of classes used in instance constants or
having a callable const constructor.
* Everything used in the bodies of extendable mixin declarations and
mixin classes.
* Possible dispatch targets of instance calls
(overrides/implementations).
Front-end server now also exposes '--dynamic-interface' option,
similar to gen_kernel tool.
Also, this change includes a couple of minor fixes:
* Typo in ast.dart.
* In the front-end server, additional dill file specified with
'--import-dill' option is not ignored when '--link-platform' is
also used.
TEST=pkg/vm/testcases/transformations/dynamic_interface_annotator
Change-Id: I705b64efb1834dec6e0bdc5873025607f3472139
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/377761
Reviewed-by: Slava Egorov <vegorov@google.com>
Commit-Queue: Alexander Markov <alexmarkov@google.com>