Debian's Lintian packaging consistency check complains that it isn't
executable but has a #! line. In fact it's reasonable to run this
script directly, so make it executable, and put it in a _scripts
variable so it will be installed executable.
Closes: #652
Approved by: cgwalters
This test had some nondeterminism because we chose a random
object to corrupt, but because there were multiple commits, it
was possible that we chose an object that was not being pulled.
Fix this by writing some custom GJS code to find an explicitly random
object that exists in a given ref, an change a random byte offset.
This adds a lot more randomness to the testing too.