xtest: pkcs11: add symmetric cipher tests

Adds 1005, 1006 and 1007 testing symmetric ciphers via
- C_EncryptInit()
- C_Encrypt()
- C_EncryptUpdate()
- C_EncryptFinal()
- C_DecryptInit()
- C_Decrypt()
- C_DecryptUpdate()
- C_DecryptFinal()

Reviewed-by: Vesa Jääskeläinen <vesa.jaaskelainen@vaisala.com>
Co-developed-by: Etienne Carriere <etienne.carriere@linaro.org>
Signed-off-by: Etienne Carriere <etienne.carriere@linaro.org>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>