Add more assertions to the property storage use in arrays
https://bugs.webkit.org/show_bug.cgi?id=107728

Reviewed by Filip Pizlo.

Add a bunch of assertions to array and object butterfly
usage.  This should make debugging somewhat easier.

I also converted a couple of assertions to release asserts
as they were so low cost it seemed a sensible thing to do.

* runtime/JSArray.cpp:
(JSC::JSArray::sortVector):
(JSC::JSArray::compactForSorting):
* runtime/JSObject.h:
(JSC::JSObject::getHolyIndexQuickly):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@141029 268f45cc-cd09-0410-ab3c-d52691b4dbfc