win: let UV_PROCESS_WINDOWS_HIDE hide consoles

The existing UV_PROCESS_WINDOWS_HIDE flag only applies to
executables linked to the WINDOWS subsystem. This allows
CONSOLE subsystem applications to pop up a console
window. This commit sets the CREATE_NO_WINDOW process
flag when UV_PROCESS_WINDOWS_HIDE to prevent this behavior.

Refs: nodejs/node#15380
Refs: joyent/libuv#627
Refs: libuv#965
PR-URL: libuv#1558
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Bartosz Sosnowski <bartosz@janeasystems.com>

src/win/process.c

@@ -1058,15 +1058,18 @@ int uv_spawn(uv_loop_t* loop,
   startup.hStdOutput = uv__stdio_handle(process->child_stdio_buffer, 1);
   startup.hStdError = uv__stdio_handle(process->child_stdio_buffer, 2);
 
+  process_flags = CREATE_UNICODE_ENVIRONMENT;
+
   if (options->flags & UV_PROCESS_WINDOWS_HIDE) {
     /* Use SW_HIDE to avoid any potential process window. */
     startup.wShowWindow = SW_HIDE;
+
+    /* Hide console windows. */
+    process_flags |= CREATE_NO_WINDOW;
   } else {
     startup.wShowWindow = SW_SHOWDEFAULT;
   }
 
-  process_flags = CREATE_UNICODE_ENVIRONMENT;
-
   if (options->flags & UV_PROCESS_DETACHED) {
     /* Note that we're not setting the CREATE_BREAKAWAY_FROM_JOB flag. That
      * means that libuv might not let you create a fully daemonized process