test/static: replace seed corpus with repository

From the beginning seed corpus for fuzzing tests is located
in a Tarantool repository. However, it was not practical:
binary data was mixed with Tarantool's source code and made
size of the repository bigger. The patch moves the seed corpus to
an external repository [1]. Everyone who wants to execute fuzzing
testing locally can be able to clone a repository with the seed
corpus.

1. https://github.com/ligurio/tarantool-corpus

Needed by tarantool#10911

NO_CHANGELOG=testing
NO_DOC=testing
NO_TEST=testing

Author: ligurio