Do not mix CRLF and LF header endings in a couple of HTTP tests

Do not mix CRLF and LF header endings in a couple of HTTP tests

Consistently use CRLF instead. The mixed endings weren't
documented so I assume they were unintentional.

This change doesn't matter for curl itself but makes using
the tests with a proxy between curl and the test server
more convenient.

Tests that consistently use no carriage returns were
left unmodified as one can easily work around this.