Add operators test to source_mapping_test.

tests/compiler/dart2js/sourcemaps/operators_test_file.dart

+// Copyright (c) 2015, 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.
+
+// Test file for testing source mappings of operations.
+
+var counter = 0;
+
+void record(result) {
+  counter++;
+}
+
+main(args) {
+  counter++;
+  operations(args.length > 0,
+      0, 1.5, args[0], new Complex(0, 1), new Complex(1.5, 2.5));
+  return counter;
+}
+
+void operations(cond, a, b, c, d, e) {
+  if (cond) record(a + a);
+  if (cond) record(a + b);
+  if (cond) record(a + c);
+  if (cond) record(a + d);
+  if (cond) record(a + e);
+  if (cond) record(b + a);
+  if (cond) record(b + b);
+  if (cond) record(b + c);
+  if (cond) record(b + d);
+  if (cond) record(b + e);
+  if (cond) record(c + a);
+  if (cond) record(c + b);
+  if (cond) record(c + c);
+  if (cond) record(c + d);
+  if (cond) record(c + e);
+  if (cond) record(d + a);
+  if (cond) record(d + b);
+  if (cond) record(d + c);
+  if (cond) record(d + d);
+  if (cond) record(d + e);
+  if (cond) record(e + a);
+  if (cond) record(e + b);
+  if (cond) record(e + c);
+  if (cond) record(e + d);
+  if (cond) record(e + e);
+}
+
+class Complex {
+  final num re;
+  final num im;
+
+  const Complex(this.re, this.im);
+
+  operator +(Complex other) => new Complex(re + other.re, im + other.im);
+
+  // TODO(johnniwinther): Support implicit null check in '=='.
+  //operator ==(Complex other) => re == other.re && im == other.im;
+
+  int get hashCode => 13 * re.hashCode + 17 * im.hashCode;
+}