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
Using this option (only available in debug builds) makes curl always
call curl_easy_duphandle() on the handle before using it.
To help us catch curl_easy_duphandle() mistakes better.
Add a CI job using this.
Bonus: the previous runtests option -e is now also supported as
--test-event
Closes#15504
