This change moves the fuzzing_spa_packets file from the test/fuzzing/
directory into the perl FKO extension t/ directory and is now referenced
directly by the t/04_fuzzing.t test file. The test suite itself also uses
this file for fuzzing tests as well, but having the FKO built-in tests
enables Test::Valgrind memory checks so it is useful to have this included
in the FKO sources. (When the FKO module is submitted to CPAN, it should
not depend on non-local files, but it's ok for the test suite to reference
the ../perl/FKO/t/ directory.)