dict_sys_tables_type_to_tf(): Change the parameter n_cols to not_redundant.

dict_tf_is_valid_not_redundant(): Refactored from dict_tf_is_valid().

dict_sys_tables_type_valid(): Replaces dict_sys_tables_type_validate().
Use the common function dict_tf_is_valid_not_redundant(), which validates
PAGE_COMPRESSION_LEVEL more strictly.

DICT_TF_GET_UNUSED(flags): Remove.