This reverts commit 0b9a75e8781593c250f6366a64a019018ade688e.
Thanks to the previous fixes ("REGTESTS: Fix truncated.vtc to send 0-CRLF" and
"BUG/MINOR: mux-h2: Properly handle full or truncated HTX messages on shut"),
this script can be reenabled for FreeBSD.