Do not add extra argument for new.target

src/x64/builtins-x64.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/code-factory.h"
 #include "src/codegen.h"
@@ skipping 509 matching lines @@
     // Copy arguments and receiver to the expression stack.
     Label loop, entry;
     __ movp(rcx, rax);
     __ jmp(&entry);
     __ bind(&loop);
     __ Push(Operand(rbx, rcx, times_pointer_size, 0));
     __ bind(&entry);
     __ decp(rcx);
     __ j(greater_equal, &loop);
 
-    __ incp(rax);  // Pushed new.target.
-
     // Handle step in.
     Label skip_step_in;
     ExternalReference debug_step_in_fp =
         ExternalReference::debug_step_in_fp_address(masm->isolate());
     __ Move(kScratchRegister, debug_step_in_fp);
     __ cmpp(Operand(kScratchRegister, 0), Immediate(0));
     __ j(equal, &skip_step_in);
 
     __ Push(rax);
     __ Push(rdi);
     __ Push(rdi);
     __ CallRuntime(Runtime::kHandleStepInForDerivedConstructors, 1);
     __ Pop(rdi);
     __ Pop(rax);
 
     __ bind(&skip_step_in);
 
     // Call the function.
     ParameterCount actual(rax);
     __ InvokeFunction(rdi, actual, CALL_FUNCTION, NullCallWrapper());
 
     // Restore context from the frame.
     __ movp(rsi, Operand(rbp, StandardFrameConstants::kContextOffset));
 
-    __ movp(rbx, Operand(rsp, 0));  // Get arguments count.
-  }                                 // Leave construct frame.
+    // Get arguments count, skipping over new.target.
+    __ movp(rbx, Operand(rsp, kPointerSize));  // Get arguments count.
+  }                                            // Leave construct frame.
 
   // Remove caller arguments from the stack and return.
   __ PopReturnAddressTo(rcx);
   SmiIndex index = masm->SmiToIndex(rbx, rbx, kPointerSizeLog2);
   __ leap(rsp, Operand(rsp, index.reg, index.scale, 1 * kPointerSize));
   __ PushReturnAddressFrom(rcx);
   __ ret(0);
 }
 
 
@@ skipping 1216 matching lines @@
   __ ret(0);
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64