[debugger] flood function for stepping before calling it.

src/x64/builtins-x64.cc

Index: src/x64/builtins-x64.cc
diff --git a/src/x64/builtins-x64.cc b/src/x64/builtins-x64.cc
index e22bb59a4d7d155bd2ed2887da29277ef0ab03d3..9c933cb2229aa8a0f1b98762f353e1b4f034bbe3 100644
--- a/src/x64/builtins-x64.cc
+++ b/src/x64/builtins-x64.cc
@@ -332,7 +332,8 @@ static void Generate_JSConstructStubHelper(MacroAssembler* masm,
       __ Call(code, RelocInfo::CODE_TARGET);
     } else {
       ParameterCount actual(rax);
-      __ InvokeFunction(rdi, rdx, actual, CALL_FUNCTION, NullCallWrapper());
+      __ InvokeFunction(rdi, rdx, actual, CALL_FUNCTION,
+                        CheckDebugStepCallWrapper());
     }
 
     // Store offset of return address for deoptimizer.
@@ -1733,10 +1734,11 @@ void Builtins::Generate_CallFunction(MacroAssembler* masm,
 
   __ LoadSharedFunctionInfoSpecialField(
       rbx, rdx, SharedFunctionInfo::kFormalParameterCountOffset);
-  __ movp(r8, FieldOperand(rdi, JSFunction::kCodeEntryOffset));
   ParameterCount actual(rax);
   ParameterCount expected(rbx);
-  __ InvokeCode(r8, no_reg, expected, actual, JUMP_FUNCTION, NullCallWrapper());
+
+  __ InvokeFunctionCode(rdi, no_reg, expected, actual, JUMP_FUNCTION,
+                        CheckDebugStepCallWrapper());
 
   // The function is a "classConstructor", need to raise an exception.
   __ bind(&class_constructor);