* cipher/cipher.c (_gcry_cipher_ctl): Add handling for
'PRIV_CIPHERCTL_GET_COUNTER'.
* src/gcrypt-testapi.h (PRIV_CIPHERCTL_GET_COUNTER): New.
* tests/basic.c (cipher_cbc_bulk_test, cipher_cfb_bulk_test): Restore
IV checks by reading current IV from CBC/CFB cipher handle using
PRIV_CIPHERCTL_GET_INPUT_VECTOR.
(cipher_ctr_bulk_test): Restore counter checks by reading current
counter from CTR cipher handle using PRIV_CIPHERCTL_GET_COUNTER.