[gzip] Fix access of small compressed files (#45937). * src/gzip/ftgzip.c (ft_gzip_stream_close): Avoid memory leak. (ft_gzip_get_uncompressed_file): Correct byte order while reading unsigned long value. Without this change, the whole optimization of accessing small files in `FT_Stream_OpenGzip' is never executed! As a consequence, access to PCF files in general (which are normally small files) should be much improved now as originally intended.