Make mbedtls_test_err_add_check fail tests
Make mbedtls_test_err_add_check fail tests

Previously an error message was printed and then the test manually exited
via `mbedtls_exit( 1 )`. This commit includes a rebase onto:
540320bf7b5de6d3dbd78abb3e5527674189d09c so that `mbedtls_test_fail` can
be used instead to properly fail tests (and report them as such).

Signed-off-by: Chris Jones <cbf609b812bf58762ceb89e8692559dbbe9149ea@arm.com>

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