Remove runtime function from fuzzing

Don't do fuzzing of _IsStringWrapperSafeForDefaultValueOf as it expects a non-smi as its first argument.
Review URL: http://codereview.chromium.org/3109010

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@5253 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

test/mjsunit/fuzz-natives.js

@@ -174,6 +174,9 @@ var knownProblems = {
   // This function performs some checks compile time (it requires its first
   // argument to be a compile time smi).
   "_GetFromCache": true,
+
+  // This function expects its first argument to be a non-smi.
+  "_IsStringWrapperSafeForDefaultValueOf" : true
 };
 
 var currentlyUncallable = {