Enable preaging of code objects when --optimize-for-size.

src/x64/codegen-x64.cc

Index: src/x64/codegen-x64.cc
diff --git a/src/x64/codegen-x64.cc b/src/x64/codegen-x64.cc
index 247c7a234a6943ecc9492101a3cdcb981ad1120d..5923bfdb4ec14e995a5fbcd4ca52362973b60083 100644
--- a/src/x64/codegen-x64.cc
+++ b/src/x64/codegen-x64.cc
@@ -678,8 +678,6 @@ void MathExpGenerator::EmitMathExp(MacroAssembler* masm,
 #undef __
 
 
-static const int kNoCodeAgeSequenceLength = 6;
-
 static byte* GetNoCodeAgeSequence(uint32_t* length) {
   static bool initialized = false;
   static byte sequence[kNoCodeAgeSequenceLength];
@@ -736,11 +734,8 @@ void Code::PatchPlatformCodeAge(Isolate* isolate,
     Code* stub = GetCodeAgeStub(isolate, age, parity);
     CodePatcher patcher(sequence, young_length);
     patcher.masm()->call(stub->instruction_start());
-    for (int i = 0;
-         i < kNoCodeAgeSequenceLength - Assembler::kShortCallInstructionLength;
-         i++) {
-      patcher.masm()->nop();
-    }
+    patcher.masm()->Nop(
+        kNoCodeAgeSequenceLength - Assembler::kShortCallInstructionLength);
   }
 }