Fix special handling of DefineOwnProperty on arrays.

Fix special handling of DefineOwnProperty on arrays.

According to the ES5 spec the implementation of DefineOwnProperty() has
to special case handling of arrays. This is a preliminary implementation
correctly handling definition of array index properties, defining length
properties is not completely covered yet.

R=rossberg@chromium.org
TEST=test262

Committed: http://code.google.com/p/v8/source/detail?r=9596

[Michael Starzinger, 2011-10-10 13:01:57]

With this fix the situation looks like this. Not enough to bump us to
the top of the Test262 results, but we should score second place now.

Total: 33363 tests
 *    0 tests will be skipped
 *    0 tests are expected to timeout sometimes
 *   12 tests are expected to be flaky but not crash
 * 32604 tests are expected to pass
 *  198 tests are expected to fail that we won't fix
 *  540 tests are expected to fail that we should fix

[rossberg, 2011-10-10 13:12:38]

lgtm