Don’t call get-magic on a referenced array in chdir, etc.

Don’t call get-magic on a referenced array in chdir, etc.

Commit 557fbd17eb added the MAYBE_DEREF_GV macro, which 2ea1cce
applied to chdir, chmod and chown.

That macro calls get-magic on its arguments checks to see if it might
be a gv or ref and, if it’s a ref, calls get-magic on the referent,
to see whether it will turn into a gv.  That means we’ll end up with
chdir($array_obj) calling get-magic on the array.  While probably
harmless, calling get-magic is superfluous and probably incorrect.  I
don’t know that there is a reasonable way to test this.