lib: add timedOut flag on child process spawn

Author: FranciscoMateusVG

lib/child_process.js

@@ -764,6 +764,7 @@ function spawn(file, args, options) {
     let timeoutId = setTimeout(() => {
       if (timeoutId) {
         try {
+          child.timedOut = true;
           child.kill(killSignal);
         } catch (err) {
           child.emit('error', err);

lib/internal/child_process.js

@@ -263,6 +263,7 @@ function ChildProcess() {
   this.exitCode = null;
   this.killed = false;
   this.spawnfile = null;
+  this.timedOut = false;
 
   this._handle = new Process();
   this._handle[owner_symbol] = this;