Additional changes to temporarily enable running tests:
ssl_srv.c and test_suite_ecdh use mbedtls_ecp_group_load instead of
mbedtls_ecdh_setup
test_suite_ctr_drbg uses mbedtls_ctr_drbg_update instead of
mbedtls_ctr_drbg_update_ret
The main goal with these tests is to test the bug in question and
they are not meant to test the entire PKCS#1 v1.5 behaviour. To
achieve full test coverage, further test cases are needed.