Move kernel baseline tests to front_end.

pkg/front_end/testcases/rasta/bad_setter_initializer.dart.outline.expect

 library;
 import self as self;
 import "dart:core" as core;
 
 class C extends core::Object {
   constructor •() → void
     ;
   set field(dynamic value) → dynamic
     ;
 }
 static method main() → dynamic
   ;