Reviewed by Oliver Hunt.

        Took some responsibilities away from NewSpace
        https://bugs.webkit.org/show_bug.cgi?id=62325
        
        NewSpace is basically just an allocator now.
        
        Heap acts as a controller, responsible for managing the set of all
        MarkedBlocks.
        
        This is in preparation for moving parts of the controller logic into
        separate helper classes that can act on arbitrary sets of MarkedBlocks
        that may or may not be in NewSpace.

        * heap/Heap.cpp:
        (JSC::Heap::Heap):
        (JSC::Heap::destroy):
        (JSC::Heap::allocate):
        (JSC::Heap::markRoots):
        (JSC::Heap::clearMarks):
        (JSC::Heap::sweep):
        (JSC::Heap::objectCount):
        (JSC::Heap::size):
        (JSC::Heap::capacity):
        (JSC::Heap::collect):
        (JSC::Heap::resetAllocator):
        (JSC::Heap::allocateBlock):
        (JSC::Heap::freeBlocks):
        (JSC::Heap::shrink): Moved the set of MarkedBlocks from NewSpace to Heap,
        along with all functions that operate on the set of MarkedBlocks. Also
        moved responsibility for deciding whether to allocate a new MarkedBlock,
        and for allocating it.

        * heap/Heap.h:
        (JSC::Heap::contains):
        (JSC::Heap::forEach): Ditto.

        * heap/NewSpace.cpp:
        (JSC::NewSpace::addBlock):
        (JSC::NewSpace::removeBlock):
        (JSC::NewSpace::resetAllocator):
        * heap/NewSpace.h:
        (JSC::NewSpace::waterMark):
        (JSC::NewSpace::allocate): Ditto.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@88389 268f45cc-cd09-0410-ab3c-d52691b4dbfc