Revert "Move dart2js from sdk/lib/_internal/compiler to pkg/compiler"

tests/compiler/dart2js/mixin_typevariable_test.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library mixin_typevariable_test;
 
 import 'package:expect/expect.dart';
 import "package:async_helper/async_helper.dart";
 import 'type_test_helper.dart';
-import 'package:compiler/src/dart_types.dart';
-import "package:compiler/src/elements/elements.dart"
+import 'package:compiler/implementation/dart_types.dart';
+import "package:compiler/implementation/elements/elements.dart"
        show Element, ClassElement;
 
 void main() {
   testMixinSupertypes();
   testNonTrivialSubstitutions();
 }
 
 void testMixinSupertypes() {
   asyncTest(() => TypeEnvironment.create(r"""
       class S<S_T> {}
       class M1<M1_T> {}
       class M2<M2_T> {}
       class M3<M3_T> {}
-
+      
       class C1<C1_T> extends S<C1_T> with M1<C1_T>, M2<C1_T>, M3<C1_T> {}
       class C2<C2_T> = S<C2_T> with M1<C2_T>, M2<C2_T>, M3<C2_T>;
       """, expectNoWarningsOrErrors: true).then((env) {
 
     ClassElement Object = env.getElement('Object');
     ClassElement S = env.getElement('S');
     ClassElement M1 = env.getElement('M1');
     ClassElement M2 = env.getElement('M2');
     ClassElement M3 = env.getElement('M3');
     ClassElement C1 = env.getElement('C1');
@@ skipping 34 matching lines @@
     testSupertypes(C2_S_M1_M2);
     testSupertypes(C2);
   }));
 }
 
 void testNonTrivialSubstitutions() {
   asyncTest(() => TypeEnvironment.create(r"""
       class _ {}
       class A<A_T> {}
       class B<B_T, B_S> {}
-
+      
       class C1<C1_T> extends A with B {}
       class C2<C2_T> = A with B;
-
+      
       class D1<D1_T> extends A<D1_T> with B<D1_T, A<D1_T>> {}
       class D2<D2_T> = A<D2_T> with B<D2_T, A<D2_T>>;
-
+      
       class E1<E1_T> extends A<_> with B<_, A<_>> {}
       class E2<E2_T> = A<_> with B<_, A<_>>;
-
+      
       class F1<F1_T> extends A<_> with B<_, B<F1_T, _>> {}
       class F2<F2_T> = A<_> with B<_, B<F2_T, _>>;
       """, expectNoWarningsOrErrors: true).then((env) {
     DartType _dynamic = env['dynamic'];
     DartType _ = env['_'];
 
     ClassElement Object = env.getElement('Object');
     ClassElement A = env.getElement('A');
     ClassElement B = env.getElement('B');
     ClassElement C1 = env.getElement('C1');
@@ skipping 49 matching lines @@
     testSupertypes(E2, {A: [_], B: [_, instantiate(A, [_])]});
 
     DartType F1_T = F1.typeVariables.first;
     testSupertypes(F1, {A: [_], B: [_, instantiate(B, [F1_T, _])]});
     DartType F1_superclass_T = F1.superclass.typeVariables.first;
     testSupertypes(F1.superclass, {A: [_], B: [_, instantiate(B, [F1_superclass_T, _])]});
     DartType F2_T = F2.typeVariables.first;
     testSupertypes(F2, {A: [_], B: [_, instantiate(B, [F2_T, _])]});
   }));
 }