Reviewed by Sam Weinig.

        - https://bugs.webkit.org/show_bug.cgi?id=20993
          Array.push/pop need optimized cases for JSArray

        3% or so speedup on DeltaBlue benchmark.

        * kjs/ArrayPrototype.cpp:
        (JSC::arrayProtoFuncPop): Call JSArray::pop when appropriate.
        (JSC::arrayProtoFuncPush): Call JSArray::push when appropriate.

        * kjs/JSArray.cpp:
        (JSC::JSArray::putSlowCase): Set m_fastAccessCutoff when appropriate, getting
        us into the fast code path.
        (JSC::JSArray::pop): Added.
        (JSC::JSArray::push): Added.
        * kjs/JSArray.h: Added push and pop.

        * kjs/operations.cpp:
        (JSC::throwOutOfMemoryError): Don't inline this. Helps us avoid PIC branches.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@36778 268f45cc-cd09-0410-ab3c-d52691b4dbfc