Implement type inference for "not" expressions.

pkg/front_end/testcases/inference/infer_binary_double_double.dart

 // Copyright (c) 2017, 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.
 
 /*@testedFeatures=inference*/
 library test;
 
 var /*@topType=bool*/ a_equal = 1.0 /*@target=num::==*/ == 2.0;
 var /*@topType=bool*/ a_notEqual = 1.0 /*@target=num::==*/ != 2.0;
 var /*@topType=double*/ a_add = 1.0 /*@target=double::+*/ + 2.0;
 var /*@topType=double*/ a_subtract = 1.0 /*@target=double::-*/ - 2.0;
 var /*@topType=double*/ a_multiply = 1.0 /*@target=double::**/ * 2.0;
 var /*@topType=double*/ a_divide = 1.0 /*@target=double::/ */ / 2.0;
 var /*@topType=int*/ a_floorDivide = 1.0 /*@target=double::~/ */ ~/ 2.0;
 var /*@topType=bool*/ a_greater = 1.0 /*@target=num::>*/ > 2.0;
 var /*@topType=bool*/ a_less = 1.0 /*@target=num::<*/ < 2.0;
 var /*@topType=bool*/ a_greaterEqual = 1.0 /*@target=num::>=*/ >= 2.0;
 var /*@topType=bool*/ a_lessEqual = 1.0 /*@target=num::<=*/ <= 2.0;
 var /*@topType=double*/ a_modulo = 1.0 /*@target=double::%*/ % 2.0;
+
+main() {
+  a_equal;
+  a_notEqual;
+  a_add;
+  a_subtract;
+  a_multiply;
+  a_divide;
+  a_floorDivide;
+  a_greater;
+  a_less;
+  a_greaterEqual;
+  a_lessEqual;
+  a_modulo;
+}