lib/fuzzing: Free memory after successful load in fuzz_tiniparser

Otherwise we have a memory leak and so fail the Google oss-fuzz check_build test.

Signed-off-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>

Autobuild-User(master): Jeremy Allison <jra@samba.org>
Autobuild-Date(master): Mon Nov 18 21:02:52 UTC 2019 on sn-devel-184
