Test AD too long only when CCM_ALT not defined
Test AD too long only when CCM_ALT not defined

Since the AD too long is a limitation on Mbed TLS,
HW accelerators may support this. Run the test for AD too long,
only if `MBEDTLS_CCM_ALT` is not defined.
Addresses comment in #1996.

Mbed-TLS/mbedtls,ARMmbed/mbedtls,NXPmicro/mbedtls,Mbed-TLS/mbedtls,NXPmicro/mbedtls,NXPmicro/mbedtls,Mbed-TLS/mbedtls,NXPmicro/mbedtls,ARMmbed/mbedtls,ARMmbed/mbedtls,ARMmbed/mbedtls,Mbed-TLS/mbedtls