By making them look less like http headers, the hyper mode "tweak"
doesn't interfere.
Enable test 2002 and 2003 in hyper builds (and 1280 which is unrelated
but should be enabled).
Closes#7658
The tftpd test server now logs all received options and thus all TFTP
test cases need to match them exactly.
Extended test 283 to use and verify --tftp-blksize.
I've now made TFTP "connections" not being kept for re-use within libcurl.
TFTP is UDP-based so the benefit was really low (if even existing) to begin
with so instead of tracking down to fix this problem we instead removed the
re-use. I also enabled test case 1099 that I wrote a few days ago to verify
that this change fixes the reported problem.
