When in doubt, refer to the source of run-tests.php and its commit
history. The big hint here is that FILEEOF replaces \r and \n with ''
helly added it to test for bug #35382 (which I found by searching the
commit log at cvs.php.net first for FILEEOF and then for 35382):
http://cvs.php.net/viewvc.cgi/php-src/run-tests.php?r1=1.237&r2=1.238
It looks like at the time, the test would pass when it should fail if
the comment line ended with \n or with \r or with \r\n. The same is
true of the comments2.phpt test - the problem being tested for is the
lexer failing when there is nothing after the closing bracket }.
I confirm this historical fact. So this section is really needed and it's used in a few places already.
Nuno