Reviewed by Sam Weinig.

        Rolled back in r79627 now that the underlying cause for it crashing is fixed.
        https://bugs.webkit.org/show_bug.cgi?id=55159

        * JavaScriptCore.exp:
        * JavaScriptCore.vcproj/JavaScriptCore/JavaScriptCore.def:
        * JavaScriptCore.xcodeproj/project.pbxproj:
        * runtime/Heap.cpp:
        (JSC::Heap::allocateSlowCase):
        * runtime/Heap.h:
        * runtime/JSCell.h:
        (JSC::JSCell::MarkedSpace::sizeClassFor):
        (JSC::JSCell::Heap::allocate):
        (JSC::JSCell::JSCell::operator new):
        * runtime/MarkedBlock.h:
        * runtime/MarkedSpace.cpp:
        (JSC::MarkedSpace::MarkedSpace):
        (JSC::MarkedSpace::allocateBlock):
        (JSC::MarkedSpace::reset):
        * runtime/MarkedSpace.h:
        (JSC::MarkedSpace::SizeClass::SizeClass):


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@80052 268f45cc-cd09-0410-ab3c-d52691b4dbfc