Asymmetric keys can't just be arbitrary byte strings: the public key
has to match the private key and the private key usually has
nontrivial constraints.
In order to have deterministic test data and not to rely on
cryptographic dependencies in the Python script, hard-code some test
keys.
In this commit, copy some test keys from test_suite_psa_crypto.data.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>