On Windows XP SP1 a ShellExecute() call that is supposed to fail
succeeds instead. This means the child process is started but
ShellExecute() returns without waiting for it, resulting in a race
condition on the child's results file. So use our shell_execute_ex()
wrapper instead as it always waits for the child process.
Signed-off-by: Francois Gouget <fgouget@free.fr>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>