X64: Disable crankshaft if serializerion is enabled.

Review URL: http://codereview.chromium.org/6413017

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@6665 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/x64/cpu-x64.cc

@@ -43,6 +43,9 @@ namespace internal {
 
 void CPU::Setup() {
   CpuFeatures::Probe(true);
+  if (Serializer::enabled()) {
+    V8::DisableCrankshaft();
+  }
 }