tests: Add 2k RSA key working in FIPS mode.
* tests/basic.c (check_pubkey): The 1k RSA keys are no longer supposed to be working so have a new 2k one that should work. Taken from ciper/rsa.c's sample_secret_key.
- GnuPG-bug-id: T5512
- Signed-off-by: Jakub Jelen <jjelen@redhat.com>