runtests.pl: reverse line-ending conversion on Windows

It makes more sense to convert the expected output to [CR][LF] on
Windows than to force the actual, probably correct, output to [LF].

This way it is actually possible to see if curl outputs the correct
line-ending excepted by a text-aware test case.
ftpserver.pl: directory LISTings use [CR][LF] for ASCII transfer

According to section 2.2 of RFC959 the End-of-Line is defined as:
 The end-of-line sequence defines the separation of printing
 lines.  The sequence is Carriage Return, followed by Line Feed.

Verified by sniffing traffic between a Windows FTP client (FileZilla)
and Unix-hosted FTP server (ProFTPD).
runtests.pl: added support for text-mode within datacheck section
FTP tests: enable text-mode for data and datacheck sections