Remove support for operator negate and replace occurrences with unary

runtime/lib/integers.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.
 
 // TODO(srdjan): fix limitations.
 // - shift amount must be a Smi.
 class IntegerImplementation {
   factory IntegerImplementation._uninstantiable() {
     throw const UnsupportedOperationException(
         "IntegerImplementation can only be allocated by the VM");
@@ skipping 15 matching lines @@
   }
   num operator /(num other) {
     return this.toDouble() / other.toDouble();
   }
   num operator %(num other) {
     if ((other is int) && (other == 0)) {
       throw const IntegerDivisionByZeroException();
     }
     return other.moduloFromInteger(this);
   }
-  int operator negate() {
+  int operator -() {
     return 0 - this;
   }
   int operator &(int other) {
     return other.bitAndFromInteger(this);
   }
   int operator |(int other) {
     return other.bitOrFromInteger(this);
   }
   int operator ^(int other) {
     return other.bitXorFromInteger(this);
@@ skipping 189 matching lines @@
     }
   }
   int shlFromInt(int other) {
     throw const OutOfMemoryException();
   }
 
   int pow(int exponent) {
     throw "Bigint.pow not implemented";
   }
 }