(aka BUG#11766883)
  - fix review comments
  - Rewrite last usage of handler::get_tablespace_name to use
    table->s->tablespace directly
  - Remove(revert) the addition of default implementation for
    handler::get_tablespace_name
  - Add comments describing the new TABLE_SHARE members default_storage_media
    and tablespace
  - Fix usage of incorrect mask for column_format bits, i.e COLUMN_FORMAT_MASK