Fixed ASSERT failure I just introduced.
        
        Made the fastMalloc isForbidden flag per thread. (Oops!) We expect that
        other threads will malloc while we're marking -- we just want to prevent
        our own marking from malloc'ing.

        * wtf/FastMalloc.cpp:
        (WTF::initializeIsForbiddenKey):
        (WTF::isForbidden):
        (WTF::fastMallocForbid):
        (WTF::fastMallocAllow):
        (WTF::fastMalloc):
        (WTF::fastCalloc):
        (WTF::fastFree):
        (WTF::fastRealloc):
        (WTF::do_malloc):



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@20020 268f45cc-cd09-0410-ab3c-d52691b4dbfc