Problem: Crash when 'fileformat' is forced to "dos" and the first line in
the file is empty and does not have a CR character.
Solution: Don't check for CR before the start of the buffer.
Problem: The test for patch 8.0.0224 misses the CR characters and passes
even without the fix. (Christian Brabandt)
Solution: Use double quotes and \<CR>.
Problem: When 'fileformats' is changed in a BufReadPre auto command, it
does not take effect in readfile(). (Gary Johnson)
Solution: Check the value of 'fileformats' after executing auto commands.
(Christian Brabandt)
