Move kernel baseline tests to front_end.

pkg/front_end/testcases/rasta/bad_explicit_super_constructor.dart.dartk.expect

 library;
 import self as self;
 import "dart:core" as core;
 
 class A extends core::Object {
   constructor •(dynamic x) → dynamic
     : super core::Object::•()
     ;
 }
 class B extends self::A {
   const constructor •() → dynamic
     : invalid-initializer
     ;
 }
 static method main() → dynamic {
   new self::B::•();
   const self::B::•();
 }