Don't pass the hole to SetElement when creating Array.observe change records

test/mjsunit/regress/regress-356589.js

Index: test/mjsunit/regress/regress-356589.js
diff --git a/test/mjsunit/regress/regress-3220.js b/test/mjsunit/regress/regress-356589.js
similarity index 86%
copy from test/mjsunit/regress/regress-3220.js
copy to test/mjsunit/regress/regress-356589.js
index 6f8e8c8f0eedd2cd5e00cb00d9e9fee1899a27c6..f93c5456407e6f1a433aa2c63d84f0749489a19b 100644
--- a/test/mjsunit/regress/regress-3220.js
+++ b/test/mjsunit/regress/regress-356589.js
@@ -25,6 +25,10 @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-// Flags: --use-strict
+// This test passes if it does not crash in debug mode
 
-String(new Date());
+arr = ['a', 'b', 'c', 'd'];
+Object.defineProperty(arr.__proto__, '0', { get: function(){} });
+Object.defineProperty(arr, '2', {get: function(){} });
+Object.observe(arr, function() {});
+arr.length = 2;