Reviewed by Sam Weinig.

        A little more Heap refactoring
        https://bugs.webkit.org/show_bug.cgi?id=53577
        
        SunSpider reports no change.
        
        Split out MarkedBlock into its own file / class.
        
        Did the following renames:
            isCellMarked => isMarked
            checkMarkCell => testAndSetMarked
            markCell => setMarked
            cellOffset => cellNumber
            collectorBlock => blockFor

        * Android.mk:
        * CMakeLists.txt:
        * GNUmakefile.am:
        * JavaScriptCore.gypi:
        * JavaScriptCore.pro:
        * JavaScriptCore.vcproj/JavaScriptCore/JavaScriptCore.vcproj:
        * JavaScriptCore.xcodeproj/project.pbxproj:
        * runtime/Heap.cpp:
        (JSC::WeakGCHandlePool::update):
        * runtime/Heap.h:
        (JSC::Heap::isMarked):
        (JSC::Heap::testAndSetMarked):
        (JSC::Heap::setMarked):
        * runtime/JSArray.h:
        (JSC::MarkStack::markChildren):
        (JSC::MarkStack::drain):
        * runtime/JSCell.h:
        (JSC::JSCell::MarkStack::internalAppend):
        * runtime/MarkedBlock.cpp: Added.
        * runtime/MarkedBlock.h: Added.
        (JSC::MarkedBlock::blockFor):
        (JSC::MarkedBlock::cellNumber):
        (JSC::MarkedBlock::isMarked):
        (JSC::MarkedBlock::testAndSetMarked):
        (JSC::MarkedBlock::setMarked):
        (JSC::MarkedBlock::isCellAligned):
        (JSC::MarkedBlock::isPossibleCell):
        * runtime/MarkedSpace.h:
        (JSC::MarkedSpace::isMarked):
        (JSC::MarkedSpace::testAndSetMarked):
        (JSC::MarkedSpace::setMarked):
        * runtime/SmallStrings.cpp:
        (JSC::isMarked):
        * runtime/WeakGCMap.h:
        (JSC::WeakGCMap::isValid):
        (JSC::::get):
        (JSC::::take):
        (JSC::::set):


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@77391 268f45cc-cd09-0410-ab3c-d52691b4dbfc