(check_composing_code): Fix previous change. Now it

(check_composing_code): Fix previous change.  Now it
alwasy returns 0 or -1.
(decode_coding_iso2022): Adjusted for the above change.
(encode_coding_iso2022): When encoding the last block, flush out
tailing garbage bytes.
(setup_coding_system): Delete unnecessary code.
(shrink_decoding_region): Check translation table.  If ASCII
should be translated, give up shrinking.
(shrink_encoding_region): Likewise.
(SHRINK_CONVERSION_REGION_THRESHHOLD): New macro.
(SHRINK_CONVERSION_REGION): New macro.
(code_convert_region): Call SHRINK_CONVERSION_REGION.  Delete text
properties here.
(code_convert_region): In the case of encoding, always calulate
correct character number.
(code_convert_string): Call SHRINK_CONVERSION_REGION.
(code_convert_region1): Don't delete text properties here.
(check_composing_code): Fix previous change.  Now it
alwasy returns 0 or -1.
(decode_coding_iso2022): Adjusted for the above change.
(encode_coding_iso2022): When encoding the last block, flush out
tailing garbage bytes.
(setup_coding_system): Delete unnecessary code.
(shrink_decoding_region): Check translation table.  If ASCII
should be translated, give up shrinking.
(shrink_encoding_region): Likewise.
(SHRINK_CONVERSION_REGION_THRESHHOLD): New macro.
(SHRINK_CONVERSION_REGION): New macro.
(code_convert_region): Call SHRINK_CONVERSION_REGION.  Delete text
properties here.
(code_convert_region): In the case of encoding, always calulate
correct character number.
(code_convert_string): Call SHRINK_CONVERSION_REGION.
(code_convert_region1): Don't delete text properties here.