Testcase for Array push() max array length
Testcase for writing invalid array length

The Array exotic [[DefineOwnProperty]] must capture and reject such
writes with RangeError.  Handling for this is integrated into Duktape's
"putprop" algorithm and also defineProperty().  Other internals must
either use "putprop" or implement a similar check carefully.
Improve Array push() max length testcase
Comment updates for Array push() and FIXMEs
Testcase for deleting plain buffer elements
Reject plain buffer item deletions (non-config)
Release note: plain buffer index deletes
Some object code XXX comments
Testcase for a large Object.defineProperties()
Minor tweak to Object.defineProperties()

Push the internal Object.defineProperty() function only once outside the
loop to work better with large Object.defineProperty() calls.  The
different is quite small in practice.

It would be better to avoid creating a function object in the first place,
but since we call Object.defineProperty() internally we need the original,
unchanged Object.defineProperty() in case the user has overwritten it.
Downgrade final duk_hobject_props.c FIXME

Writing to array entries using Object.defineProperty() (or
Object.defineProperties()) now causes an array part to be
abandoned.  This is certainly not preferable behavior, but
not a 1.0 release blocker, so fixing this can be done in 1.1.
Document array defineProperty() limitation
Merge branch 'hobject-fixme-cleanup'