Serial.list() doesn't update items after a port gets disconnected

Issue description

if conncted to a port say "COM5". if "COM5" is disconncted for any reason, the serial.list() will still show that "COM5" exists even if connction is stopped using serial.stop() after getting "COM5" device disconncted.

again, if conncted to port "COM5" for instance, if connection is stopped using serial.stop() and then if "COM5" device is disconnceted, serial.list() will then update its element and "COM5" isn't there anymore. which is a normal behavior.

test code to varify this issue

import processing.serial.*;
 Serial comPort;

void setup() {
  size(500, 400);
  surface.setTitle("TEST");    
  comPort = new Serial(this, "COM5", 115200);
  background(150);
  frameRate(60);
}

void draw() {
  background(150);  
  println(Serial.list().length);  
}

check for number of serial ports exists first and then try disconncting the device
Serial.list().length will still show that port was not removed...

URL(s) of affected page(s)

Proposed fix

首先，使用提供的 Processing sketch 和 Serial.list() 入口点重现问题，同时在连接处于活动状态时断开 COM5。跟踪串行库如何发现并刷新端口；当 Serial.list() 不再包含已断开的端口且无需调用 serial.stop() 时，即表示完成。