Move dart2jslib parts into separate libraries.

tests/compiler/dart2js/unparser2_test.dart

Index: tests/compiler/dart2js/unparser2_test.dart
diff --git a/tests/compiler/dart2js/unparser2_test.dart b/tests/compiler/dart2js/unparser2_test.dart
index 88940b61e5b6b255f9843eae2879ad035104958d..ca14149ad2ede626193cb1147a45a8a0b7ebe918 100644
--- a/tests/compiler/dart2js/unparser2_test.dart
+++ b/tests/compiler/dart2js/unparser2_test.dart
@@ -6,17 +6,14 @@ import "package:expect/expect.dart";
 import "package:compiler/src/scanner/scannerlib.dart";
 import "package:compiler/src/tree/tree.dart";
 
-import "package:compiler/src/dart2jslib.dart"
-    show DiagnosticListener,
-         Script;
-
+import "package:compiler/src/diagnostic_listener.dart";
 import "package:compiler/src/elements/elements.dart"
     show CompilationUnitElement,
          LibraryElement;
-
 import "package:compiler/src/elements/modelx.dart"
     show CompilationUnitElementX,
          LibraryElementX;
+import "package:compiler/src/script.dart";
 
 main() {
   testClassDef();