Reject algorithms of the form PSA_ALG_TRUNCATED_MAC(...) or
PSA_ALG_AEAD_WITH_SHORTENED_TAG(...) when the truncation length is invalid
or not accepted by policy in Mbed TLS.
This is done in KeyType.can_do, so in generate_psa_tests.py, keys will be
tested for operation failure with this algorithm if the algorithm is
rejected, and for storage if the algorithm is accepted.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>