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/test1973

@@ -59,14 +59,14 @@ http://exam.ple.com:9000/aws_sigv4/testapi/test exam.ple.com:9000:%HOSTIP:%HTTPP
 ^Content-Type:.*
 ^Accept:.*
 </strip>
-<protocol>
-POST /aws_sigv4/testapi/test HTTP/1.1
-Host: exam.ple.com:9000
-Authorization: AWS4-HMAC-SHA256 Credential=xxx/19700101/us-east-1/s3/aws4_request, SignedHeaders=content-type;host;x-amz-content-sha256;x-amz-date, Signature=7eb34202214384872221b99a9c671b7517891ac6af56b0aff24ec51adf62b10a
-X-Amz-Date: 19700101T000000Z
-x-amz-content-sha256: 4b02e333ccf7cf530ddee3e10ebe54e935500b5e570e68650d63d743e8bbc045
-Content-Length: 12
-
+<protocol crlf="headers">
+POST /aws_sigv4/testapi/test HTTP/1.1
+Host: exam.ple.com:9000
+Authorization: AWS4-HMAC-SHA256 Credential=xxx/19700101/us-east-1/s3/aws4_request, SignedHeaders=content-type;host;x-amz-content-sha256;x-amz-date, Signature=7eb34202214384872221b99a9c671b7517891ac6af56b0aff24ec51adf62b10a
+X-Amz-Date: 19700101T000000Z
+x-amz-content-sha256: 4b02e333ccf7cf530ddee3e10ebe54e935500b5e570e68650d63d743e8bbc045
+Content-Length: 12
+
 post fields
 </protocol>
 </verify>