tests: avoid more hard-coded CRLFs in protocol sections

- fix regex to not catch CR (from CRLF), in `PORT`, `EPRT`
  commands, allowing to use `crlf="yes"` more.
- add `crlf="headers"` mode for `protocol` sections.
  To call `subnewlines()` without its force option.
  This is the mode used in `data` sections when `crlf="yes"`.
  (This confusion may be subject to a future commit.)
- subnewlines: apply CRLF to `HEAD` and `CONNECT` HTTP requests.
- subnewlines: apply CRLF to RTSP requests.
- delete remaining empty `protocol` sections.

Reducing the number of `tests/data/test*`:
- CRLF newlines from 11325 to 10295. (119984 lines total)
- files with mixed newlines from 707 to 656. (1890 files total)

Follow-up to 4d2a05d3fe #19284

Closes #19318

tests/data/test985

@@ -47,8 +47,8 @@ pop3://%HOSTIP:%POP3PORT/%TESTNUMBER -u user:secret --ssl-reqd
 <errorcode>
 64
 </errorcode>
-<protocol>
-CAPA
+<protocol crlf="yes">
+CAPA
 </protocol>
 </verify>
 </testcase>