Remove the backdoor found in 5.6.0 and 5.6.1 (CVE-2024-3094).

While the backdoor was inactive (and thus harmless) without inserting
a small trigger code into the build system when the source package was
created, it's good to remove this anyway:

  - The executable payloads were embedded as binary blobs in
    the test files. This was a blatant violation of the
    Debian Free Software Guidelines.

  - On machines that see lots bots poking at the SSH port, the backdoor
    noticeably increased CPU load, resulting in degraded user experience
    and thus overwhelmingly negative user feedback.

  - The maintainer who added the backdoor has disappeared.

  - Backdoors are bad for security.

This reverts the following without making any other changes:

The sentence "This was a blatant violation of the Debian Free Software Guidelines" is highlighted.

Below the github screenshot is a frame of the 1998 film The Big Lebowski with the meme caption "What, are you a fucking park ranger now?" from the scene where that line was spoken.