Add a fuzzing harness for Tor
I have a branch for this, we held off on releasing it publicly because it made the underlying bug in #20384 (moved) obvious.
Now we've had time for people to upgrade to 0.2.8.9 (and various other patched versions), we can release the fuzzing code.
To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information