Revert "Fix bad type-inferrence for logical expressions."

tests/language/logical_expression3_test.dart

-// Copyright (c) 2014, 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.
-
-import "package:expect/expect.dart";
-
-int globalCounter = 0;
-
-bool nonInlinedNumTypeCheck(Object object) {
-  if (new DateTime.now().millisecondsSinceEpoch == 42) {
-    return nonInlinedNumTypeCheck(object);
-  }
-  return object is num;
-}
-
-int confuse(x) {
-  if (new DateTime.now().millisecondsSinceEpoch == 42) return confuse(x - 1);
-  return x;
-}
-
-main() {
-  var o = [ "foo", 499 ][confuse(0)];
-
-  // When the lhs of a logical or fails, it must not assume that all negative is
-  // checks in it, have failed.
-  // Here, the `o is! num` check succeeds, but the length test failed.
-  if ((o is! num && o.length == 4) ||
-      (nonInlinedNumTypeCheck(o))) {
-    Expect.fail("Type-check failed");
-  }
-}