Adjust RUN-PROGRAM with a string COMMAND on Windows
Always go through CMD in that case, including on Allegro and CLISP, since the previous behavior is simultaneously non-portable, error-prone and limited; better to provide a portable well-defined abstraction. Users who want more can use the (bad) implementation-specific interfaces, or IOlib. Simplify the call to RUN-PROGRAM. Add a PARAMETER-ERROR to %NORMALIZE-COMMAND on unsupported platforms.