tests: use crlf=yes attribute more

To make special newlines more explicit and visible.
Mostly in `<protocol>` sections, some in `<data*>` and `<upload>`.

Reducing the number of `tests/data/test*`:
- CRLF newlines from 21535 to 11337.
- files with mixed newlines from 1335 to 707.

Also delete empty `<protocol>` sections.

Closes #19284

tests/data/test647

@@ -42,11 +42,11 @@ It may contain any type of data.
 s/^--------------------------[A-Za-z0-9]*/------------------------------/
 s/boundary=------------------------[A-Za-z0-9]*/boundary=----------------------------/
 </strippart>
-<protocol>
-A001 CAPABILITY
-A002 LOGIN user secret
-A003 APPEND %TESTNUMBER (\Seen) {940}
-A004 LOGOUT
+<protocol crlf="yes">
+A001 CAPABILITY
+A002 LOGIN user secret
+A003 APPEND %TESTNUMBER (\Seen) {940}
+A004 LOGOUT
 </protocol>
 <upload>
 Content-Type: multipart/mixed; boundary=----------------------------