Run a some tests with -DFUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION

The fuzzers use -DFUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION, and actually
get different results based on that. We should have at least some
targets that actually fully use the fuzz corpora.

Reviewed-by: Rich Salz <rsalz@openssl.org>
GH: #2023