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

tests/compiler/dart2js/value_range2_test.dart

Index: tests/compiler/dart2js/value_range2_test.dart
diff --git a/tests/compiler/dart2js/value_range2_test.dart b/tests/compiler/dart2js/value_range2_test.dart
index dfc2fdea4dd4526ae8e10da970ede82b5906e86d..5bebf99f843b3297f3a6fe7930dd9b0d77ee8f7e 100644
--- a/tests/compiler/dart2js/value_range2_test.dart
+++ b/tests/compiler/dart2js/value_range2_test.dart
@@ -3,9 +3,9 @@
 // BSD-style license that can be found in the LICENSE file.
 
 import "package:expect/expect.dart";
-import "package:compiler/src/ssa/ssa.dart";
-import "package:compiler/src/dart2jslib.dart";
-import "package:compiler/src/js_backend/js_backend.dart";
+import "package:compiler/implementation/ssa/ssa.dart";
+import "package:compiler/implementation/dart2jslib.dart";
+import "package:compiler/implementation/js_backend/js_backend.dart";
 
 ValueRangeInfo info = new ValueRangeInfo(const JavaScriptConstantSystem());