Infer the types of initializing formals from the corresponding fields.

pkg/front_end/testcases/covariant_generic.dart.outline.expect

 library;
 import self as self;
 import "dart:core" as core;
 
 typedef Callback = <T extends core::Object>(T) → void;
 class Foo<T extends core::Object> extends core::Object {
   final field self::Foo::T finalField;
   final field (self::Foo::T) → void callbackField;
   field self::Foo::T mutableField;
   field (self::Foo::T) → void mutableCallbackField;
-  constructor •(dynamic finalField, dynamic callbackField) → void
+  constructor •(self::Foo::T finalField, (self::Foo::T) → void callbackField) → void
     ;
   method method(self::Foo::T x) → void
     ;
   set setter(self::Foo::T x) → dynamic
     ;
   method withCallback((self::Foo::T) → void callback) → void
     ;
 }
 static method main() → dynamic
   ;