Update Windows ap_filedup() call to recognise when it is asked to dup2

a standard i/o handle. Return error if the dup2 handle is not one of the
standard i/o handles (because Windows does not support a dup2 style function
to operate on native file handles)


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@84638 13f79535-47bb-0310-9956-ffa450edef68