Restructure pkg/unittest and pkg/webdriver to follow the pub conventions.

pkg/fixnum/int64.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 fixnum;
+
 /**
  * An immutable 64-bit signed integer, in the range [-2^63, 2^63 - 1].
  * Arithmetic operations may overflow in order to maintain this range.
  */
 class int64 implements intx {
 
   // A 64-bit integer is represented internally as three non-negative
   // integers, storing the 22 low, 22 middle, and 20 high bits of the
   // 64-bit value.  _l (low) and _m (middle) are in the range
   // [0, 2^22 - 1] and _h (high) is in the range [0, 2^20 - 1].
@@ skipping 1071 matching lines @@
         }
       }
       return ZERO;
     }
 
     // Generate the quotient using bit-at-a-time long division.
     return _divModHelper(aIsCopy ? a : new int64._copy(a), b, negative,
         aIsNegative, aIsMinValue, computeRemainder);
   }
 }