[php-src] PR #23902: Fix gzfile() truncating lines with NUL bytes and splitting long lines

Pull Request: https://github.com/php/php-src/pull/23902 Author: lacatoire gzfile() reads each line into a fixed 8192-byte buffer with php_stream_gets() and stores it with add_index_string(), which recomputes the length with strlen(). This causes two bugs: - A NUL byte in the line silently truncates everything after it. - Lines longer than 8190 bytes are split into multiple array entries. file() already avoids both issues by using php_stream_get_line() with a NULL/0 buffer (dynamically sized) and add_index_stringl() (explicit length). This applies the same approach to gzfile(). Reproducer: \\\`php <?php \$data = "before\0after\nline2\n"; file_put_contents('n.gz', gzencode(\$data)); var_dump(array_map('bin2hex', gzfile('n.gz'))); // drops everything from \0 onward \\\` A regression test is included covering NUL preservation (checked against gzgets() output) and a 20001-byte line staying as a single array entry.