timers: fix unref() memory leak

The destructor isn't being called for timers that have been unref'd.

Fixes: #8364
Signed-off-by: Trevor Norris <trev.norris@gmail.com>

Author: trevnorris

icu_config.gypi

@@ -0,0 +1,2 @@
+# Do not edit. Generated by the configure script.
+{ 'variables': { }}

lib/timers.js

@@ -290,6 +290,14 @@ var Timeout = function(after) {
   this._repeat = false;
 };
 
+
+function unrefdHandle() {
+  this.owner._onTimeout();
+  if (!this.owner.repeat)
+    this.owner.close();
+}
+
+
 Timeout.prototype.unref = function() {
   if (!this._handle) {
 
@@ -303,7 +311,8 @@ Timeout.prototype.unref = function() {
     if (delay < 0) delay = 0;
     exports.unenroll(this);
     this._handle = new Timer();
-    this._handle.ontimeout = this._onTimeout;
+    this._handle.owner = this;
+    this._handle.ontimeout = unrefdHandle;
     this._handle.start(delay, 0);
     this._handle.domain = this.domain;
     this._handle.unref();