Restrict MD5 in x509 certificates

Remove support for X509 certificates signed with MD5.
Issue raised by Harm Verhagen
diff --git a/tests/suites/test_suite_x509parse.data b/tests/suites/test_suite_x509parse.data
index 717cd6f..7920fc6 100644
--- a/tests/suites/test_suite_x509parse.data
+++ b/tests/suites/test_suite_x509parse.data
@@ -417,11 +417,11 @@
 
 X509 Certificate verification #12 (Valid Cert MD4 Digest)
 depends_on:POLARSSL_MD4_C:POLARSSL_PEM_PARSE_C:POLARSSL_SHA1_C:POLARSSL_RSA_C:POLARSSL_PKCS1_V15
-x509_verify:"data_files/cert_md4.crt":"data_files/test-ca.crt":"data_files/crl.pem":"NULL":0:0:"NULL"
+x509_verify:"data_files/cert_md4.crt":"data_files/test-ca.crt":"data_files/crl.pem":"NULL":POLARSSL_ERR_X509_CERT_VERIFY_FAILED:BADCERT_NOT_TRUSTED:"NULL"
 
 X509 Certificate verification #13 (Valid Cert MD5 Digest)
 depends_on:POLARSSL_MD5_C:POLARSSL_PEM_PARSE_C:POLARSSL_SHA1_C:POLARSSL_RSA_C:POLARSSL_PKCS1_V15
-x509_verify:"data_files/cert_md5.crt":"data_files/test-ca.crt":"data_files/crl.pem":"NULL":0:0:"NULL"
+x509_verify:"data_files/cert_md5.crt":"data_files/test-ca.crt":"data_files/crl.pem":"NULL":POLARSSL_ERR_X509_CERT_VERIFY_FAILED:BADCERT_NOT_TRUSTED:"NULL"
 
 X509 Certificate verification #14 (Valid Cert SHA1 Digest)
 depends_on:POLARSSL_SHA1_C:POLARSSL_PEM_PARSE_C:POLARSSL_SHA1_C:POLARSSL_RSA_C:POLARSSL_PKCS1_V15
@@ -723,6 +723,14 @@
 depends_on:POLARSSL_PEM_PARSE_C:POLARSSL_ECP_C:POLARSSL_ECP_DP_SECP256R1_ENABLED:POLARSSL_ECP_DP_SECP384R1_ENABLED:POLARSSL_SHA1_C:POLARSSL_SHA256_C
 x509_verify:"data_files/server5.crt":"data_files/test-ca2_cat-past-invalid.crt":"data_files/crl-ec-sha1.pem":"NULL":POLARSSL_ERR_X509_CERT_VERIFY_FAILED:BADCERT_EXPIRED:"NULL"
 
+X509 Certificate verification #88 (MD4 CRL)
+depends_on:POLARSSL_SHA256_C:POLARSSL_PEM_PARSE_C:POLARSSL_SHA1_C:POLARSSL_RSA_C:POLARSSL_PKCS1_V15
+x509_verify:"data_files/cert_sha256.crt":"data_files/test-ca.crt":"data_files/crl_md4.pem":"NULL":POLARSSL_ERR_X509_CERT_VERIFY_FAILED:BADCRL_NOT_TRUSTED:"NULL"
+
+X509 Certificate verification #89 (MD5 CRL)
+depends_on:POLARSSL_SHA256_C:POLARSSL_PEM_PARSE_C:POLARSSL_SHA1_C:POLARSSL_RSA_C:POLARSSL_PKCS1_V15
+x509_verify:"data_files/cert_sha256.crt":"data_files/test-ca.crt":"data_files/crl_md5.pem":"NULL":POLARSSL_ERR_X509_CERT_VERIFY_FAILED:BADCRL_NOT_TRUSTED:"NULL"
+
 X509 Certificate verification callback: trusted EE cert
 depends_on:POLARSSL_PEM_PARSE_C:POLARSSL_ECDSA_C:POLARSSL_SHA256_C:POLARSSL_ECP_DP_SECP256R1_ENABLED
 x509_verify_callback:"data_files/server5-selfsigned.crt":"data_files/server5-selfsigned.crt":0:"depth 0 - serial 53\:A2\:CB\:4B\:12\:4E\:AD\:83\:7D\:A8\:94\:B2 - subject CN=selfsigned, OU=testing, O=PolarSSL, C=NL\n"