Use relative URIs for core library part-of statements.

sdk/lib/core/uri.dart

 // Copyright (c) 2012, 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.
 
-part of dart.core;
+part of "core.dart";
 
 // Frequently used character codes.
 const int _SPACE = 0x20;
 const int _PERCENT = 0x25;
 const int _AMPERSAND = 0x26;
 const int _PLUS = 0x2B;
 const int _DOT = 0x2E;
 const int _SLASH = 0x2F;
 const int _COLON = 0x3A;
 const int _EQUALS = 0x3d;
@@ skipping 4614 matching lines @@
   int delta = (text.codeUnitAt(start + 4) ^ _COLON) * 3;
   delta |= text.codeUnitAt(start) ^ 0x64 /*d*/;
   delta |= text.codeUnitAt(start + 1) ^ 0x61 /*a*/;
   delta |= text.codeUnitAt(start + 2) ^ 0x74 /*t*/;
   delta |= text.codeUnitAt(start + 3) ^ 0x61 /*a*/;
   return delta;
 }
 
 /// Helper function returning the length of a string, or `0` for `null`.
 int _stringOrNullLength(String s) => (s == null) ? 0 : s.length;