Fix bug #63240 on stream_get_line()

Fix bug #63240 on stream_get_line()

stream_get_line() could contain the delimiter string if that string
had more than one character. The bug manifested itself when a read on
the stream ended with part of the delimiter string and the read after
would start with the rest of the delimiter string; provided that
the data of first read did not complete the max length result of the
call to stream_get_line() with the partial delimiter used in that max
length return. In that case, the delimiter will still appear in
the result, divided in two subsequent return values. That is not a bug.

See <http://www.mail-archive.com/internals@lists.php.net/msg61325.html>