Revert "Parts must start with 'part of'" and "Attempt to fix VM build"

dart/tests/language/prefix3_negative_test.dart

Index: dart/tests/language/prefix3_negative_test.dart
diff --git a/dart/tests/language/prefix3_negative_test.dart b/dart/tests/language/prefix3_negative_test.dart
index 73bbc09f6a41f62e011fa4e3be6be69357bdf251..f2f0e6b46d0f4fd503c72f08d703cc5a852129aa 100644
--- a/dart/tests/language/prefix3_negative_test.dart
+++ b/dart/tests/language/prefix3_negative_test.dart
@@ -7,9 +7,9 @@
 // not an error but both library1.dart and library2.dart define 'foo' which
 // results in a duplicate definition error.
 
-library Prefix3NegativeTest;
-import "library1.dart" as lib2;  // defines 'foo'.
-import "library2.dart" as lib2;  // also defines 'foo'.
+#library("Prefix3NegativeTest.dart");
+#import("library1.dart", prefix: "lib2");  // defines 'foo'.
+#import("library2.dart", prefix: "lib2");  // also defines 'foo'.
 
 
 main() {