Move kernel baseline tests to front_end.

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

-library;
-import self as self;
-import "dart:core" as core;
-
-class Foo<T extends core::Object> extends core::Object {
-  final field self::Foo::T finalField;
-  final field (self::Foo::T) → void callbackField;
-  field self::Foo::T mutableField = null;
-  field (self::Foo::T) → void mutableCallbackField = null;
-  constructor •(self::Foo::T finalField, (self::Foo::T) → void callbackField) → void
-    : self::Foo::finalField = finalField, self::Foo::callbackField = callbackField, super core::Object::•()
-    ;
-  method method(self::Foo::T x) → void {}
-  set setter(self::Foo::T x) → void {}
-  method withCallback((self::Foo::T) → void callback) → void {
-    callback.call(this.{self::Foo::finalField});
-  }
-  set mutableField$cc(core::Object mutableField_) → dynamic
-    this.{=self::Foo::mutableField} = mutableField_ as self::Foo::T;
-  method method$cc(core::Object x) → void
-    this.{=self::Foo::method}(x as self::Foo::T);
-  set setter$cc(core::Object x) → void
-    this.{=self::Foo::setter} = x as self::Foo::T;
-}
-static method main() → dynamic {
-  self::Foo<core::int> fooInt = new self::Foo::•<core::int>(1, (core::int x) → core::Null {});
-  fooInt.{self::Foo::method}(3);
-  fooInt.{self::Foo::setter} = 3;
-  fooInt.{self::Foo::withCallback}((core::int x) → core::Null {});
-  fooInt.{self::Foo::withCallback}((core::num x) → core::Null {});
-  fooInt.{self::Foo::mutableField} = 3;
-  fooInt.{self::Foo::mutableCallbackField} = (core::int x) → core::Null {};
-  self::Foo<core::num> fooNum = fooInt;
-  fooNum.{self::Foo::method$cc}(3);
-  fooNum.{self::Foo::method$cc}(2.5);
-  fooNum.{self::Foo::setter$cc} = 3;
-  fooNum.{self::Foo::setter$cc} = 2.5;
-  fooNum.{self::Foo::withCallback}((core::num x) → core::Null {});
-  fooNum.{self::Foo::mutableField$cc} = 3;
-  fooNum.{self::Foo::mutableField$cc} = 2.5;
-  fooNum.{self::Foo::mutableCallbackField}.call(3);
-  fooNum.{self::Foo::mutableCallbackField}.call(2.5);
-  fooNum.{self::Foo::mutableCallbackField} = (core::num x) → core::Null {};
-}