Reviewed by Sam.

        - convert a JavaScript immediate number to a string more efficiently

        2% speedup of Acid3 test 26

        * kjs/JSImmediate.cpp:
        (KJS::JSImmediate::toString): Take advantage of the fact that all immediate
        numbers are integers, and use the faster UString function for formatting integers
        instead of the slower one that works for floating point. I think this is a leftover
        from when immediate numbers were floating point.



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@31270 268f45cc-cd09-0410-ab3c-d52691b4dbfc