sha256-avx2: fix reading beyond end of input buffer
* cipher/sha256-avx2-bmi2-amd64.S (_gcry_sha256_transform_amd64_avx2): Use 'last block' code path if input length is only one block. * tests/basic.c (check_one_md_final): Use dynamic allocated buffer so that in future similar access errors get detected by tests/basic + valgrind.
- Reported-by: Guido Vranken <guidovranken@gmail.com>
- Signed-off-by: Jussi Kivilinna <jussi.kivilinna@iki.fi>