To make it uniform in all tests, and greppability.
Also:
- replace `-k` flag with `-q` in test 1268. (the actual flag doesn't
matter in this test)
- keep `-k` in test 300 to test its short form.
(also verified to fail without a working `-k`)
Closes#16878
missing CRs and modified %hostip
lib556/test556: use a real HTTP version to make test reuse more convenient
make sure the weekday in Date headers matches the date
test61: replace stray "^M" (5e 4d) at the end of a cookie with a '^M' (0d)
Gets the test working with external proxies like Privoxy again.
Closes#6463