Move kernel baseline tests to front_end.

pkg/kernel/testcases/strong-mode/unused_methods.baseline.txt

-library;
-import self as self;
-import "dart:core" as core;
-
-abstract class UsedAsBaseClass extends core::Object {
-  constructor •() → void
-    : super core::Object::•()
-    ;
-  abstract method usedInSubclass() → void;
-  method calledFromB() → void {
-    this.{self::UsedAsBaseClass::calledFromSubclass}();
-  }
-  abstract method calledFromSubclass() → void;
-}
-abstract class UsedAsInterface extends core::Object {
-  abstract method usedInSubclass() → void;
-}
-class InstantiatedButMethodsUnused extends core::Object {
-  constructor •() → void
-    : super core::Object::•()
-    ;
-  method usedInSubclass() → void
-    throw "Method removed by tree-shaking";
-}
-class ClassA extends self::UsedAsBaseClass implements self::UsedAsInterface, self::InstantiatedButMethodsUnused {
-  constructor •() → void
-    : super self::UsedAsBaseClass::•()
-    ;
-  method usedInSubclass() → void {
-    core::print("A");
-  }
-}
-class ClassB extends self::UsedAsBaseClass implements self::UsedAsInterface, self::InstantiatedButMethodsUnused {
-  constructor •() → void
-    : super self::UsedAsBaseClass::•()
-    ;
-  method usedInSubclass() → void {
-    core::print("B");
-    this.{self::UsedAsBaseClass::calledFromB}();
-  }
-  method calledFromSubclass() → void {}
-}
-static method baseClassCall(self::UsedAsBaseClass object) → void {
-  object.{self::UsedAsBaseClass::usedInSubclass}();
-}
-static method interfaceCall(self::UsedAsInterface object) → void {
-  object.{self::UsedAsInterface::usedInSubclass}();
-}
-static method exactCallA(self::ClassA object) → void {
-  object.{self::ClassA::usedInSubclass}();
-}
-static method exactCallB(self::ClassB object) → void {
-  object.{self::ClassB::usedInSubclass}();
-}
-static method usedTopLevel() → dynamic {}
-static method main() → dynamic {
-  self::usedTopLevel();
-  self::ClassA a = new self::ClassA::•();
-  self::exactCallA(a);
-  self::baseClassCall(a);
-  self::interfaceCall(a);
-  self::ClassB b = new self::ClassB::•();
-  self::exactCallB(b);
-  self::baseClassCall(b);
-  self::interfaceCall(b);
-  new self::InstantiatedButMethodsUnused::•();
-}