1.0.28.2: fix bug 201, Incautious type inference from compound types

1.0.28.2: fix bug 201, Incautious type inference from compound types

 * Define LVAR-CONSERVATIVE-TYPE &co, which take into accound that a
   function call can change the type of a cons or a non-simple array
   without changing it's identity. Use this instead of LVAR-TYPE in
   derive-type optimizers for CAR and CDR, and in the ARRAY-DIMENSIONS
   transform. (There may be other places where it should be used as
   well, but I could not find anything else just now.)