Optimize isFinite and isNaN.

src/isolate.cc

Index: src/isolate.cc
diff --git a/src/isolate.cc b/src/isolate.cc
index d36690297782ae5367d84d6260ed28b4c61cb5d8..09cbc8a1e65b70d52bb813be5bcf7912f2e92c5c 100644
--- a/src/isolate.cc
+++ b/src/isolate.cc
@@ -1409,6 +1409,7 @@ Isolate::Isolate()
       global_handles_(NULL),
       context_switcher_(NULL),
       thread_manager_(NULL),
+      ast_sentinels_(NULL),
       string_tracker_(NULL),
       regexp_stack_(NULL),
       embedder_data_(NULL) {
@@ -1545,6 +1546,9 @@ Isolate::~Isolate() {
   delete regexp_stack_;
   regexp_stack_ = NULL;
 
+  delete ast_sentinels_;
+  ast_sentinels_ = NULL;
+
   delete descriptor_lookup_cache_;
   descriptor_lookup_cache_ = NULL;
   delete context_slot_cache_;
@@ -1706,6 +1710,7 @@ bool Isolate::Init(Deserializer* des) {
   bootstrapper_ = new Bootstrapper();
   handle_scope_implementer_ = new HandleScopeImplementer(this);
   stub_cache_ = new StubCache(this);
+  ast_sentinels_ = new AstSentinels();
   regexp_stack_ = new RegExpStack();
   regexp_stack_->isolate_ = this;