Correct, tests that require "default host and port" can no longer run (unless by a fluke the random port happens to land on the single port the test can run on). They need to be adjusted to work on "any" port number.
This allows us to make test cases to use base64 at run-time and still
use and verify information determined at run-time, such as the IMAP test
server's port number in test 842.
ftpserver.pl is adjusted to load test instructions and test number from
the preprocessed test file.
FILEFORMAT.md now documents the new base64 encoding syntax.
Reported-by: Marcel Raad