To untangle the different curl/server requirements of these tests.
Also to make this test run for non-H2 builds. Searching the cause of
the flakiness documented in #19481.
Also:
- fix the callback function prototype. Detected by ASAN with this patch,
though the issue was pre-existing.
```
lib/cw-out.c:211:14: runtime error: call to function emptyWriteFunc
through pointer to incorrect function type
'unsigned long (*)(char *, unsigned long, unsigned long, void *)'
tests/libtest/lib2405.c:72: note: emptyWriteFunc defined here
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior lib/cw-out.c:211:14
```
Ref: https://github.com/curl/curl/actions/runs/19296686908/job/55180334364?pr=19487#step:44:3768
Follow-up to 96a5ce5a82#19481Closes#19487
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
Check responsiveness of http/3 server when running.
Also, a test case with http/2 or http/3 server requirement
now implicitly drags in a 'http' server and we need no longer
mention that in testdata.
Closes#15058
