Reviewed by Adam.

    Reviewed by Adam.

        - use __declspec(thread) for fast thread-local storage on Windows

        - 2.2% speedup on sunspider (on Windows)
        - 7% speedup on the string section
        - 6% speedup on JS iBench

        - fixed <rdar://problem/5473084> PLT on Windows got 2.5% slower between r25406 and r25422
        - fixed at least some of <rdar://5527965? i-Bench JS was 14% slower in 310A11 than 310A10

        * wtf/FastMalloc.cpp:
        (WTF::getThreadHeap):
        (WTF::setThreadHeap):
        (WTF::TCMalloc_ThreadCache::GetCache):
        (WTF::TCMalloc_ThreadCache::GetCacheIfPresent):
        (WTF::TCMalloc_ThreadCache::CreateCacheIfNecessary):

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@26760 268f45cc-cd09-0410-ab3c-d52691b4dbfc