0.9.18.9: Pathname Love on Win32

0.9.18.9: Pathname Love on Win32
 * Namestring simplification (was UNIX-SIMPLIFY-PATHNAME) is now
   function of the host. Shamelessly cargo-culted Win32 version from
   the Unix version.
 * Kludged %ENUMERATE-DIRECTORIES to work with :WILD-INFERIORS on
   Win32.
 * Fix UNPARSE-NATIVE-WIN32-NAMESTRING to handle #P"X:\\FOO" case
   correctly. ("X:\\FOO", not "X:\\\\FOO")
 * Missing NEWS entry for 0.9.18.8.
 * Correct order of arguments to MERGE-PATHNAMES in SYSINIT-PATHNAME.
 * Couple of WITH-TEST additions to test-suite.