* **Electron Version:**
  * 5.0.0-beta5
* **Operating System:**
  * Windows 10 (1803) x64, Raspberry Pi Debian Stretch
* **Last Known Working Electron version:**:
  * 3.0.3

### Expected Behavior
Starting electron with --inspect=XXXX or --inspect-brk=XXXX should open the port XXXX for connecting with a debugger that supports the inspect protocol (e.g. VS Code).

### Actual Behavior
If --inspect=XXXX or --inspect-brk=XXXX is supplied the opened port is always 9229 regardless of the supplied port XXXX. Depending on --inspect or inspect-brk the application starts or waits. Without supplying either no port is opened

### To Reproduce
Start electron with the arguments stated above.
atom/browser/node_debugger.cc
#include "atom/browser/node_debugger.h"
#include <memory>
#include <string>
#include <vector>
#include "atom/common/node_includes.h"
#include "base/command_line.h"
#include "base/logging.h"
#include "base/strings/string_util.h"
#include "base/strings/utf_string_conversions.h"
#include "libplatform/libplatform.h"
#include "native_mate/dictionary.h"
namespace atom {
NodeDebugger::NodeDebugger(node::Environment* env) : env_(env) {}
NodeDebugger::~NodeDebugger() {}
void NodeDebugger::Start() {
  auto* inspector = env_->inspector_agent();
  if (inspector == nullptr)
    return;
  std::vector<std::string> args;
  for (auto& arg : base::CommandLine::ForCurrentProcess()->argv()) {
#if defined(OS_WIN)