Revert "Rename internal library dart:_collection-dev to dart:_internal."

sdk/lib/_internal/lib/collection_dev_patch.dart

Index: sdk/lib/_internal/lib/collection_dev_patch.dart
diff --git a/sdk/lib/_internal/lib/collection_dev_patch.dart b/sdk/lib/_internal/lib/collection_dev_patch.dart
deleted file mode 100644
index cd766c48d6fad220319415c7617c135bdbe62373..0000000000000000000000000000000000000000
--- a/sdk/lib/_internal/lib/collection_dev_patch.dart
+++ /dev/null
@@ -1,14 +0,0 @@
-// 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.
-
-import 'dart:_js_primitives' show printString;
-
-patch class Symbol implements core.Symbol {
-  patch const Symbol(String name)
-      : this._name = name;
-}
-
-patch void printToConsole(String line) {
-  printString('$line');
-}