test: set stdin too for pseudo-tty tests

Ref: https://github.com/nodejs/node/pull/10037
Ref: https://github.com/nodejs/node/pull/10146
PR-URL: https://github.com/nodejs/node/pull/10149
Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Italo A. Casas <me@italoacasas.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>

tools/test.py

@@ -683,11 +683,12 @@ def Execute(args, context, timeout=None, env={}, faketty=False):
   if faketty:
     import pty
     (out_master, fd_out) = pty.openpty()
-    fd_err = fd_out
+    fd_in = fd_err = fd_out
     pty_out = out_master
   else:
     (fd_out, outname) = tempfile.mkstemp()
     (fd_err, errname) = tempfile.mkstemp()
+    fd_in = 0
     pty_out = None
 
   # Extend environment
@@ -699,6 +700,7 @@ def Execute(args, context, timeout=None, env={}, faketty=False):
     context,
     timeout,
     args = args,
+    stdin = fd_in,
     stdout = fd_out,
     stderr = fd_err,
     env = env_copy,