Revert "Make patch file import declarations apply to the patched library too."

tests/compiler/dart2js_extra/math_lib_prefix_test.dart

Index: tests/compiler/dart2js_extra/math_lib_prefix_test.dart
diff --git a/tests/compiler/dart2js_extra/math_lib_prefix_test.dart b/tests/compiler/dart2js_extra/math_lib_prefix_test.dart
deleted file mode 100644
index c8db94491b10056bcf60716017e5114b44114acf..0000000000000000000000000000000000000000
--- a/tests/compiler/dart2js_extra/math_lib_prefix_test.dart
+++ /dev/null
@@ -1,10 +0,0 @@
-// Copyright (c) 2011, 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.
-
-#import("dart:math", prefix: "foo");
-
-main() {
-  Expect.equals(2.0, foo.sqrt(4));
-  Expect.equals(2.25, foo.pow(1.5, 2.0));
-}