Allow binary operators on compile-time-constants.

tests/language/src/CompileTimeConstant3Test.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.
+
+final x = 19.5;
+final y = 3.3;
+final g1 = x + y;
+final g2 = x * y;
+final g3 = x / y;
+final g4 = x ~/ y;
+final g5 = -x;
+final g6 = x < y;
+final g7 = x <= y;
+final g8 = x <= x;
+final g9 = x > y;
+final g10 = x >= y;
+final g11 = x >= x;
+final g12 = x == y;
+final g13 = x == x;
+final g14 = x != y;
+final g15 = x != x;
+final g16 = g1 + g2 + g3 + g4 + g5;
+final g17 = x % y;
+
+main() {
+  Expect.equals(22.8, g1);
+  Expect.equals(64.35, g2);
+  Expect.equals(5.909090909090909, g3);
+  Expect.equals(5.0, g4);
+  Expect.equals(-19.5, g5);
+  Expect.equals(false, g6);
+  Expect.equals(false, g7);
+  Expect.equals(true, g8);
+  Expect.equals(true, g9);
+  Expect.equals(true, g10);
+  Expect.equals(true, g11);
+  Expect.equals(false, g12);
+  Expect.equals(true, g13);
+  Expect.equals(true, g14);
+  Expect.equals(false, g15);
+  Expect.equals(78.5590909090909, g16);
+  Expect.equals(3.000000000000001, g17);
+}