Avoid flushing the icache unnecessarily when updating target addresses in code.

src/x64/assembler-x64.h

Index: src/x64/assembler-x64.h
diff --git a/src/x64/assembler-x64.h b/src/x64/assembler-x64.h
index d844d92599640fe6940318c56f379213e23ae98a..6d2745be1dfe3e753c81c3fa13dfc3fdcebb3330 100644
--- a/src/x64/assembler-x64.h
+++ b/src/x64/assembler-x64.h
@@ -518,16 +518,20 @@ class Assembler : public AssemblerBase {
                                           ConstantPoolArray* constant_pool);
   static inline void set_target_address_at(Address pc,
                                            ConstantPoolArray* constant_pool,
-                                           Address target);
+                                           Address target,
+                                           ICacheFlushMode icache_flush_mode =
+                                               FLUSH_ICACHE_IF_NEEDED) ;
   static inline Address target_address_at(Address pc, Code* code) {
     ConstantPoolArray* constant_pool = code ? code->constant_pool() : NULL;
     return target_address_at(pc, constant_pool);
   }
   static inline void set_target_address_at(Address pc,
                                            Code* code,
-                                           Address target) {
+                                           Address target,
+                                           ICacheFlushMode icache_flush_mode =
+                                               FLUSH_ICACHE_IF_NEEDED) {
     ConstantPoolArray* constant_pool = code ? code->constant_pool() : NULL;
-    set_target_address_at(pc, constant_pool, target);
+    set_target_address_at(pc, constant_pool, target, icache_flush_mode);
   }
 
   // Return the code target address at a call site from the return address