Create frequently used symbols in the vm isolate

vm/intermediate_language_x64.cc

Index: vm/intermediate_language_x64.cc
===================================================================
--- vm/intermediate_language_x64.cc	(revision 9729)
+++ vm/intermediate_language_x64.cc	(working copy)
@@ -13,6 +13,7 @@
 #include "vm/object_store.h"
 #include "vm/parser.h"
 #include "vm/stub_code.h"
+#include "vm/symbols.h"
 
 #define __ compiler->assembler()->
 
@@ -312,7 +313,7 @@
                                  comp->cid(),
                                  comp->token_pos(),
                                  comp->try_index());
-  const String& operator_name = String::ZoneHandle(String::NewSymbol("=="));
+  const String& operator_name = String::ZoneHandle(Symbols::New("=="));
   const int kNumberOfArguments = 2;
   const Array& kNoArgumentNames = Array::Handle();
   const int kNumArgumentsChecked = 2;
@@ -605,7 +606,7 @@
     return;
   }
   const String& function_name =
-      String::ZoneHandle(String::NewSymbol(Token::Str(kind())));
+      String::ZoneHandle(Symbols::New(Token::Str(kind())));
   compiler->AddCurrentDescriptor(PcDescriptors::kDeopt,
                                  cid(),
                                  token_pos(),
@@ -802,7 +803,7 @@
 static void EmitStoreIndexedGeneric(FlowGraphCompiler* compiler,
                                     StoreIndexedComp* comp) {
   const String& function_name =
-      String::ZoneHandle(String::NewSymbol(Token::Str(Token::kASSIGN_INDEX)));
+      String::ZoneHandle(Symbols::New(Token::Str(Token::kASSIGN_INDEX)));
 
   compiler->AddCurrentDescriptor(PcDescriptors::kDeopt,
                                  comp->cid(),