Fixed http://bugs.webkit.org/show_bug.cgi?id=15902
        15% of string-validate-input.js is spent compiling the same regular expression
        
        Store a compiled representation of the regular expression in the AST.
        
        Only a .2% SunSpider speedup overall, but a 10.6% speedup on 
        string-validate-input.js.

        * kjs/nodes.cpp:
        (KJS::RegExpNode::evaluate):
        * kjs/nodes.h:
        (KJS::RegExpNode::):
        * kjs/nodes2string.cpp:
        (KJS::RegExpNode::streamTo):
        * kjs/regexp.cpp:
        (KJS::RegExp::flags):
        * kjs/regexp.h:
        (KJS::RegExp::pattern):
        * kjs/regexp_object.cpp:
        (KJS::RegExpObjectImp::construct):
        (KJS::RegExpObjectImp::createRegExpImp):
        * kjs/regexp_object.h:



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@27702 268f45cc-cd09-0410-ab3c-d52691b4dbfc