procutil: use rapply(tonativestr, ...) to preserve lists when they come in

This was broken when script was a list instead of a string. I caught this
with an internal extension at Google, and I'm not really sure why it wasn't
caught in any kind of CI.

Differential Revision: https://phab.mercurial-scm.org/D9471

mercurial/utils/procutil.py

@@ -640,7 +640,7 b' if pycompat.iswindows:'
         # we can't use close_fds *and* redirect stdin. I'm not sure that we
         # need to because the detached process has no console connection.
         p = subprocess.Popen(
-            tonativestr(script),
+            pycompat.rapply(tonativestr, script),
             shell=shell,
             env=tonativeenv(env),
             close_fds=True,