Remove support for operator negate and replace occurrences with unary

tests/language/naming_test.dart

 // 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.
 
 class A {
   A() { NamingTest.count++; }
   foo(a, b) {
     Expect.equals(1, a);
     Expect.equals(2, b);
   }
@@ skipping 159 matching lines @@
     Expect.equals(42, bug.x);
   }
 }
 
 class Hoisting {
   var f_;
   Hoisting.negate(var x) {
     f_ = () { return x; };
   }
 
-  // TODO(hausner): Rename to operator -.
-  operator negate() {
+  operator -() {
     var x = 3;
     return () { return x + 1; };
   }
 
   operator[] (x) {
     return () { return x + 3; };
   }
 
   static void test() {
     var h = new Hoisting.negate(1);
@@ skipping 284 matching lines @@
 
 // Test that the generated JS names don't conflict with "$"
 class DartQuery {
   Object wrapped;
   DartQuery(this.wrapped);
 
   $add(Object other) => other;
   $negate() => wrapped;
 
   operator +(Object other) => 123;
-  operator negate() => 444;
+  operator -() => 444;
 }
 
 $add(Object first, Object second) => second;
 DartQuery $(Object obj) => new DartQuery(obj);
 
 // Ensure we don't have false positive. named constructor and methods
 // are in different namespaces, therefore it is ok to have a method
 // called foo and a named constructor CLASS.foo
 class Naming1Test {
   Naming1Test.foo() { }
@@ skipping 21 matching lines @@
         // NoSuchMethodError.
         (e) => e is ObjectNotClosureException || e is NoSuchMethodError);
   }
 }
 
 main() {
   NamingTest.testMain();
   Naming1Test.main(null);
   Naming2Test.main(null);
 }