https://bugs.webkit.org/show_bug.cgi?id=77488

Reviewed by Geoffrey Garen.

Source/JavaScriptCore: 

* JavaScriptCore.exp:
* runtime/JSArray.cpp:
(JSC::JSArray::finalize): Added finalizer.
(JSC::JSArray::allocateSparseMap): Factored out code for allocating new sparse maps.
(JSC):
(JSC::JSArray::deallocateSparseMap): Factored out code for deallocating sparse maps.
(JSC::JSArray::enterDictionaryMode): Renamed enterSparseMode to enterDictionaryMode 
because the old name was confusing because we could have a sparse array that never 
called enterSparseMode.
(JSC::JSArray::defineOwnNumericProperty):
(JSC::JSArray::setLengthWritable):
(JSC::JSArray::putByIndexBeyondVectorLength):
(JSC::JSArray::setLength):
(JSC::JSArray::pop):
(JSC::JSArray::sort):
(JSC::JSArray::compactForSorting):
* runtime/JSArray.h:
(JSArray):

LayoutTests: 

* fast/js/script-tests/sparse-array.js: Added code to test oscillation between 
sparse and dense arrays.
* fast/js/sparse-array-expected.txt:


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@106496 268f45cc-cd09-0410-ab3c-d52691b4dbfc