1.0.13.38: final part of the debug-name improvements

1.0.13.38: final part of the debug-name improvements

 * Use NAME-LAMBDALIKE to construct the debug-name if :NAME is NIL.

 * Also make sure the SOURCE-NAME is not NIL, but .ANONYMOUS. if none
   is provided.

 * Correct handling of &OPTIONAL-PROCESSOR debug-names: the debug-name
   keyword is provided by the callers, so we cannot default it as part
   of the keyword parsing (in case it is NIL), additionally, even if
   we have a debug-name already, we still want to make up an
   &OPTIONAL-PROCESSOR debug-name.

 * Ensure (and strategically AVER) that we have a non-null debug-name
   for things which are .ANONYMOUS. -- by making up one using
   NAME-LAMBDALIKE if nothing else.

 * AVER that the second argument of DEBUG-NAME is not NIL.

 * Test that (COMPILE NIL '(LAMBDA ...)) doesn't make function which
   backtrace as NIL anymore.