Use kRegisterSize when calling C++ runtime

src/x64/debug-x64.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 158 matching lines @@
     __ pop(kScratchRegister);
     __ SmiToInteger32(kScratchRegister, kScratchRegister);
     __ lea(rsp, Operand(rsp, kScratchRegister, times_pointer_size, 0));
 
     // Get rid of the internal frame.
   }
 
   // If this call did not replace a call but patched other code then there will
   // be an unwanted return address left on the stack. Here we get rid of that.
   if (convert_call_to_jmp) {
-    __ addq(rsp, Immediate(kPointerSize));
+    __ addq(rsp, Immediate(kPCOnStackSize));
   }
 
   // Now that the break point has been handled, resume normal execution by
   // jumping to the target address intended by the caller and that was
   // overwritten by the address of DebugBreakXXX.
   ExternalReference after_break_target =
       ExternalReference(Debug_Address::AfterBreakTarget(), masm->isolate());
   __ movq(kScratchRegister, after_break_target);
   __ jmp(Operand(kScratchRegister, 0));
 }
@@ skipping 164 matching lines @@
 
 const bool Debug::kFrameDropperSupported = true;
 
 #undef __
 
 #endif  // ENABLE_DEBUGGER_SUPPORT
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64