Fix 64-bit bug in optimized class-check instructions.

tests/language/vm/optimized_check_class_test.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.
+// VMOptions=--optimization-counter-threshold=10 --no-use-osr
+
+import "package:expect/expect.dart";
+
+// Test dense class-id checks. Regression test for issue 22104.
+
+class A {
+  toString() => "an A";
+}
+
+class A1 extends A { }
+class A2 extends A { }
+class A3 extends A { }
+class A4 extends A { toString() => "ha"; }
+class A5 extends A { }
+class A6 extends A { }
+class A7 extends A { }
+class A8 extends A { }
+class A9 extends A { }
+class A10 extends A { }
+class A11 extends A { }
+class A12 extends A { }
+class A13 extends A { }
+class A14 extends A { }
+class A15 extends A { }
+class A16 extends A { }
+class A17 extends A { }
+class A18 extends A { }
+class A19 extends A { }
+class A20 extends A { }
+class A21 extends A { }
+class A22 extends A { }
+class A23 extends A { }
+class A24 extends A { }
+class A25 extends A { }
+class A26 extends A { }
+class A27 extends A { }
+class A28 extends A { }
+class A29 extends A { }
+class A30 extends A { }
+class A31 extends A { }
+class A32 extends A { }
+class A33 extends A { }
+class A34 extends A { }
+class A35 extends A { }
+class A36 extends A { }
+
+test_class_check(e) => e.toString();
+
+main() {
+  var list = [
+    new A1(),
+    new A2(),
+    new A11(),
+    new A36()
+  ];
+  for (var i = 0; i < list.length; i++) {
+    test_class_check(list[i]);
+  }
+  for (var i = 0; i < 100; i++) {
+    Expect.equals("an A", test_class_check(new A1()));
+  }
+  Expect.equals("ha", test_class_check(new A4()));
+}
+
+
+