Reviewed by Sam Weinig.

        - https://bugs.webkit.org/show_bug.cgi?id=20972
          speed up Arguments further by eliminating the IndexToNameMap

        No change on SunSpider. 1.29x as fast on V8 Raytrace.

        * kjs/Arguments.cpp: Moved ArgumentsData in here. Eliminated the
        indexToNameMap and hadDeletes data members. Changed extraArguments into
        an OwnArrayPtr and added deletedArguments, another OwnArrayPtr.
        Replaced numExtraArguments with numParameters, since that's what's
        used more directly in hot code paths.
        (JSC::Arguments::Arguments): Pass in argument count instead of ArgList.
        Initialize ArgumentsData the new way.
        (JSC::Arguments::mark): Updated.
        (JSC::Arguments::getOwnPropertySlot): Overload for the integer form so
        we don't have to convert integers to identifiers just to get an argument.
        Integrated the deleted case with the fast case.
        (JSC::Arguments::put): Ditto.
        (JSC::Arguments::deleteProperty): Ditto.

        * kjs/Arguments.h: Minimized includes. Made everything private. Added
        overloads for the integral property name case. Eliminated mappedIndexSetter.
        Moved ArgumentsData into the .cpp file.

        * kjs/IndexToNameMap.cpp: Emptied out and prepared for deletion.
        * kjs/IndexToNameMap.h: Ditto.

        * kjs/JSActivation.cpp:
        (JSC::JSActivation::createArgumentsObject): Elminated ArgList.

        * GNUmakefile.am:
        * JavaScriptCore.pri:
        * JavaScriptCore.vcproj/JavaScriptCore/JavaScriptCore.vcproj:
        * JavaScriptCore.xcodeproj/project.pbxproj:
        * JavaScriptCoreSources.bkl:
        * kjs/AllInOneFile.cpp:
        Removed IndexToNameMap.



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@36743 268f45cc-cd09-0410-ab3c-d52691b4dbfc