Move kernel baseline tests to front_end.

pkg/front_end/testcases/rasta/issue_000070.dart.dartk.expect

 library;
 import self as self;
 import "dart:core" as core;
 import "package:expect/expect.dart" as exp;
 
 class A<N extends core::Object, S extends core::Object, U extends core::Object> extends core::Object {
   final field core::List<self::A::U> field;
   constructor •(self::A::N n, self::A::S s) → dynamic
     : self::A::field = core::List::•<self::A::U>(), super core::Object::•() {
     exp::Expect::isTrue(n is self::A::N);
@@ skipping 21 matching lines @@
   constructor •() → self::I<self::I::H, self::I::C, self::I::K>
     : super self::J::•();
 }
 static method main() → dynamic {
   new self::A::•<core::num, core::double, core::List<dynamic>>(1, 2.0);
   self::A<dynamic, dynamic, dynamic> a = self::A::f<core::int, core::int, core::int>(1);
   const self::A::c<core::int, core::int, core::List<dynamic>>(const <dynamic>[], 1);
   dynamic z = a.getter;
   a.setter = 1;
 }