Reviewed by Geoff Garen.

        Bug 21317: Replace RegisterFile size and capacity information with Register pointers
        <https://bugs.webkit.org/show_bug.cgi?id=21317>

        This is a 2.3% speedup on the V8 DeltaBlue benchmark, a 3.3% speedup on
        the V8 Raytrace benchmark, and a 1.0% speedup on SunSpider.

        * VM/Machine.cpp:
        (JSC::slideRegisterWindowForCall):
        (JSC::Machine::callEval):
        (JSC::Machine::execute):
        (JSC::Machine::privateExecute):
        (JSC::Machine::cti_op_call_JSFunction):
        (JSC::Machine::cti_op_construct_JSConstruct):
        * VM/RegisterFile.cpp:
        (JSC::RegisterFile::~RegisterFile):
        * VM/RegisterFile.h:
        (JSC::RegisterFile::RegisterFile):
        (JSC::RegisterFile::start):
        (JSC::RegisterFile::end):
        (JSC::RegisterFile::size):
        (JSC::RegisterFile::shrink):
        (JSC::RegisterFile::grow):
        (JSC::RegisterFile::lastGlobal):
        (JSC::RegisterFile::markGlobals):
        (JSC::RegisterFile::markCallFrames):
        * kjs/JSGlobalObject.cpp:
        (JSC::JSGlobalObject::copyGlobalsTo):


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@37213 268f45cc-cd09-0410-ab3c-d52691b4dbfc