srfi-9 record compatibility with boot-9 records

srfi-9 record compatibility with boot-9 records

* module/srfi/srfi-9.scm (define-record-type): Instead of defining the
  RTD using make-vtable, use make-struct with the record-type-vtable,
  and record the type name and fields names in the vtable.  This way
  SRFI-9 records are compatible with boot-9 records.  Also we use a
  generic printer, instead of generating one anew.