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/test545

@@ -43,13 +43,13 @@ http://%HOSTIP:%HTTPPORT/%TESTNUMBER
 <strip>
 ^User-Agent:.*
 </strip>
-<protocol nonewline="yes">
-POST /%TESTNUMBER HTTP/1.1
-Host: %HOSTIP:%HTTPPORT
-Accept: */*
-Content-Length: 46
-Content-Type: application/x-www-form-urlencoded
-
+<protocol crlf="headers" nonewline="yes">
+POST /%TESTNUMBER HTTP/1.1
+Host: %HOSTIP:%HTTPPORT
+Accept: */*
+Content-Length: 46
+Content-Type: application/x-www-form-urlencoded
+
 %hex[This%00 is test binary data with an embedded NUL]hex%
 </protocol>
 </verify>