tty: avoid oob warning in TTYWrap::GetWindowSize()

PR-URL: #11454
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>

lib/tty.js

@@ -55,7 +55,7 @@ function WriteStream(fd) {
   // Ref: https://github.com/nodejs/node/pull/1771#issuecomment-119351671
   this._handle.setBlocking(process.env.NODE_TTY_UNSAFE_ASYNC !== '1');
 
-  var winSize = [];
+  var winSize = new Array(2);
   var err = this._handle.getWindowSize(winSize);
   if (!err) {
     this.columns = winSize[0];
@@ -72,7 +72,7 @@ WriteStream.prototype.isTTY = true;
 WriteStream.prototype._refreshSize = function() {
   var oldCols = this.columns;
   var oldRows = this.rows;
-  var winSize = [];
+  var winSize = new Array(2);
   var err = this._handle.getWindowSize(winSize);
   if (err) {
     this.emit('error', errnoException(err, 'getWindowSize'));