https://bugs.webkit.org/show_bug.cgi?id=19180
        speed up SunSpider by optimizing immediate number cases

        Also fixed three JavaScriptCore regressions seen on PowerPC - we didn't clip right shift
        parameter to 0...31.

        1.6% improvement on SunSpider, without significant regressions on any tests.

        * VM/Machine.cpp:
        (KJS::Machine::privateExecute):
        Added fast paths for >>, ==, ===, !=, !==. Changed order of memory accesses in many
        cases, making them less dependent on gcc's ability to properly assign registers. With this,
        I could move exception checks back into slow code paths, and saw less randomness in general.

        * kjs/JSImmediate.h:
        (KJS::JSImmediate::rightShiftImmediateNumbers):
        Added.




git-svn-id: http://svn.webkit.org/repository/webkit/trunk@34258 268f45cc-cd09-0410-ab3c-d52691b4dbfc