Add test for same CA with different keys

When a trusted CA is rolling its root keys, it could happen that for some
users the list of trusted roots contains two versions of the same CA with the
same name but different keys. Currently this is supported but wasn't tested.

Note: the intermediate file test-ca-alt.csr is commited on purpose, as not
commiting intermediate files causes make to regenerate files that we don't
want it to touch.
diff --git a/tests/suites/test_suite_x509parse.data b/tests/suites/test_suite_x509parse.data
index 3bc4cc2..7112162 100644
--- a/tests/suites/test_suite_x509parse.data
+++ b/tests/suites/test_suite_x509parse.data
@@ -759,6 +759,14 @@
 depends_on:MBEDTLS_PEM_PARSE_C:MBEDTLS_ECDSA_C:MBEDTLS_ECP_DP_SECP256R1_ENABLED:MBEDTLS_SHA256_C:MBEDTLS_SHA1_C
 x509_verify:"data_files/server5-ss-forgeca.crt":"data_files/test-int-ca3.crt":"data_files/crl-ec-sha1.pem":"NULL":MBEDTLS_ERR_X509_CERT_VERIFY_FAILED:MBEDTLS_X509_BADCERT_NOT_TRUSTED:"default":"NULL"
 
+X509 Certificate verification #91 (same CA with good then bad key)
+depends_on:MBEDTLS_PEM_PARSE_C:MBEDTLS_SHA1_C:MBEDTLS_RSA_C:MBEDTLS_PKCS1_V15:MBEDTLS_SHA256_C:MBEDTLS_ECDSA_C
+x509_verify:"data_files/server1.crt":"data_files/test-ca-good-alt.crt":"data_files/crl-ec-sha256.pem":"NULL":0:0:"compat":"NULL"
+
+X509 Certificate verification #91 (same CA with bad then good key)
+depends_on:MBEDTLS_PEM_PARSE_C:MBEDTLS_SHA1_C:MBEDTLS_RSA_C:MBEDTLS_PKCS1_V15:MBEDTLS_SHA256_C:MBEDTLS_ECDSA_C
+x509_verify:"data_files/server1.crt":"data_files/test-ca-alt-good.crt":"data_files/crl-ec-sha256.pem":"NULL":0:0:"compat":"NULL"
+
 X509 Certificate verification callback: trusted EE cert
 depends_on:MBEDTLS_PEM_PARSE_C:MBEDTLS_ECDSA_C:MBEDTLS_SHA256_C:MBEDTLS_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 - flags 0x0000\n"