Move kernel baseline tests to front_end.

pkg/front_end/testcases/DeltaBlue.dart.strong.expect

 // dynamic is not a subtype of dart.core::int (DeltaBlue.dart:139:16)
 library;
 import self as self;
 import "dart:core" as core;
 
 class DeltaBlue extends core::Object {
   constructor •() → void
     : super core::Object::•()
     ;
   method run() → void {
@@ skipping 426 matching lines @@
 }
 static method change(self::Variable v, core::int newValue) → void {
   self::EditConstraint edit = new self::EditConstraint::•(v, self::PREFERRED);
   self::Plan plan = self::planner.{self::Planner::extractPlanFromConstraints}(<self::EditConstraint>[edit]);
   for (core::int i = 0; i.{core::num::<}(10); i = i.{core::num::+}(1)) {
     v.{self::Variable::value} = newValue;
     plan.{self::Plan::execute}();
   }
   edit.{self::Constraint::destroyConstraint}();
 }