New functions are used to cover corner cases:
* authentication data is fed to gcm with 0, 1 or 2 calls to gcm_update
* ciphertext is fed to gcm with 0, 1 or 2 calls to gcm_update_ad
AES-GCM NIST test vectors downloaded at 16.06.2021 from:
csrc.nist.gov/groups/STM/cavp/documents/mac/gcmtestvectors.zip
Signed-off-by: Mateusz Starzyk <mateusz.starzyk@mobica.com>