sun.misc.CharacterDecoder.decodeBuffer should use getBytes(iso8859-1)

The fix for JDK-8036848 replaces the use of deprecated String.getBytes(int,int,byte[],int) method with String.getBytes() causes behavioral change.

sun.misc.CharacterEncoder uses "iso-8859-1" to encode from byte[] to String and CharacterDecoder uses the deprecated String.getBytes(....) to decode from String to byte[] and it works for non-ascii default encoding platform.

The sun.misc.CharacterDecoder.decode(String) method now is changed to use the default charset that will not work on platform that the default encoding is not ASCII compatible, such as the IBM ebcdic.