Add test client cert w/ SAN fields

net/data/ssl/certificates/README

 This directory contains various certificates for use with SSL-related
 unit tests.
 
 ===== Real-world certificates that need manual updating
 - google.binary.p7b
 - google.chain.pem
 - google.pem_cert.p7b
 - google.pem_pkcs7.p7b
 - google.pkcs7.p7b
 - google.single.der
@@ skipping 204 matching lines @@
 
 ===== From net/data/ssl/scripts/generate-client-certificates.sh
 - client_1.pem
 - client_1.key
 - client_1.pk8
 - client_1_ca.pem
 - client_2.pem
 - client_2.key
 - client_2.pk8
 - client_2_ca.pem
+- client_3.pem
+- client_3.key
+- client_3.pk8
+- client_3_ca.pem
      This is a set of files used to unit test SSL client certificate
      authentication.
      - client_1_ca.pem and client_2_ca.pem are the certificates of
        two distinct signing CAs.
      - client_1.pem and client_1.key correspond to the certificate and
        private key for a first certificate signed by client_1_ca.pem.
      - client_2.pem and client_2.key correspond to the certificate and
        private key for a second certificate signed by client_2_ca.pem.
      - each .pk8 file contains the same key as the corresponding .key file
        as PKCS#8 PrivateKeyInfo in DER encoding.
+     - client_3.pem is nearly identical to client_2.pem, except it is used
+       to test wifi EAP-TLS authentication so it uses a different set
+       of X509v3 extensions.  Specifically it includes two Subject
+       Alternative Name fields recognized by Chrome OS.
 
 ===== From net/data/ssl/scripts/generate-android-test-key.sh
 - android-test-key-rsa.pem
 - android-test-key-dsa.pem
 - android-test-key-dsa-public.pem
 - android-test-key-ecdsa.pem
 - android-test-key-ecdsa-public.pem
      This is a set of test RSA/DSA/ECDSA keys used by the Android-specific
      unit test in net/android/keystore_unittest.c. They are used to verify
      that the OpenSSL-specific wrapper for platform PrivateKey objects
@@ skipping 34 matching lines @@
 ===== From net/data/ssl/scripts/generate-aia-certs.sh
 - aia-cert.pem
 - aia-intermediate.der
 - aia-root.pem
      A certificate chain which we use to ensure AIA fetching works correctly
      when using NSS to verify certificates (which uses our HTTP stack).
      aia-cert.pem has a caIssuers that points to "aia-test.invalid" as the URL
      containing the intermediate, which can be served via a URLRequestFilter.
      aia-intermediate.der is stored in DER form for convenience, since that is
      the form expected of certificates discovered via AIA.