Issue title: fasta: redirecting factories are not resolved across platform.dill border
 Issue body: ```dart
main() {
  new Map();
}
```

compiles down to 

```
  static method main() → dynamic {
    cor38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5Map38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5•<dynamic, dynamic>();
  }
```

However it should actually compile down to an invocation of the `LinkedHashMap` constructor to which the `Map` redirects to.

This most likely happens because `RedirectingFactoryBody` does not actually survive serialization/deserialization when `platform.dill` is generated.
 Comments: 
 Comment 0: Good point, I'm pretty sure I know what the problem is.
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