[Isolates] Merge crankshaft (r5922 from bleeding_edge).

src/ia32/cpu-ia32.cc

Index: src/ia32/cpu-ia32.cc
diff --git a/src/ia32/cpu-ia32.cc b/src/ia32/cpu-ia32.cc
index a455580a11a3b64af88445060be6af6e15fb2f8f..286ed7b80137255cab9c495614733bcc42413fba 100644
--- a/src/ia32/cpu-ia32.cc
+++ b/src/ia32/cpu-ia32.cc
@@ -42,7 +42,12 @@ namespace v8 {
 namespace internal {
 
 void CPU::Setup() {
-  Isolate::Current()->cpu_features()->Probe();
+  CpuFeatures* cpu_features = Isolate::Current()->cpu_features();
+  cpu_features->Clear();
+  cpu_features->Probe(true);
+  if (!cpu_features->IsSupported(SSE2) || Serializer::enabled()) {
+    V8::DisableCrankshaft();
+  }
 }