Add unittests for the detection of md[2,4,5] when verifying certificates

net/data/ssl/certificates/weak_digest_sha1_ee.pem

Index: net/data/ssl/certificates/weak_digest_sha1_ee.pem
diff --git a/net/data/ssl/certificates/weak_digest_sha1_ee.pem b/net/data/ssl/certificates/weak_digest_sha1_ee.pem
new file mode 100644
index 0000000000000000000000000000000000000000..5368e62c9c10458febeebf7feb469e26abbd9c89
--- /dev/null
+++ b/net/data/ssl/certificates/weak_digest_sha1_ee.pem
@@ -0,0 +1,61 @@
+Certificate:
+    Data:
+        Version: 3 (0x2)
+        Serial Number: 1 (0x1)
+        Signature Algorithm: sha1WithRSAEncryption
+        Issuer: CN=Test Deprecated Digest Intermediate CA
+        Validity
+            Not Before: Oct 26 03:46:48 2011 GMT
+            Not After : Oct 23 03:46:48 2021 GMT
+        Subject: C=US, ST=California, L=Mountain View, O=Test CA, CN=127.0.0.1
+        Subject Public Key Info:
+            Public Key Algorithm: rsaEncryption
+            RSA Public Key: (1024 bit)
+                Modulus (1024 bit):
+                    00:c7:48:eb:5c:00:17:94:01:09:d3:bd:47:41:38:
+                    74:b8:4f:cb:ea:f1:15:eb:cb:e7:b5:6c:bd:fe:d9:
+                    97:6d:1e:1b:ee:75:9e:c1:6f:4a:5c:8c:d7:19:cf:
+                    51:89:48:e8:7d:79:41:ab:e3:a7:77:d1:de:f2:13:
+                    be:36:e7:44:c2:10:dd:56:83:03:f1:cd:e1:13:8d:
+                    fe:45:d6:1a:98:d8:8d:08:b9:32:10:36:0d:ec:ee:
+                    2d:66:22:eb:6a:0d:0e:f4:15:91:dd:9d:3e:92:db:
+                    9e:26:c8:af:4b:b7:fb:93:f8:68:07:c3:53:02:57:
+                    dc:d0:de:df:29:72:45:6f:e3
+                Exponent: 65537 (0x10001)
+        X509v3 extensions:
+            X509v3 Basic Constraints: critical
+                CA:FALSE
+            X509v3 Subject Key Identifier: 
+                35:5C:C8:0F:21:D0:A2:F5:69:44:5C:9E:B0:DC:0F:75:74:24:7A:FD
+            X509v3 Authority Key Identifier: 
+                keyid:A8:1D:06:8D:AD:3F:25:51:00:F0:3B:E9:35:C6:65:74:12:51:20:19
+
+            X509v3 Extended Key Usage: 
+                TLS Web Server Authentication, TLS Web Client Authentication
+            X509v3 Subject Alternative Name: 
+                IP Address:127.0.0.1
+    Signature Algorithm: sha1WithRSAEncryption
+        ab:a4:58:6a:d8:f4:87:00:11:45:23:ea:75:a9:0d:cd:87:73:
+        0e:73:f2:97:d3:74:b0:cd:90:c9:45:83:03:c3:82:ee:2f:79:
+        51:31:12:1c:39:a0:e2:45:f2:c2:4e:70:8c:e4:f3:af:15:4c:
+        be:5d:e7:c3:96:79:c8:a4:98:6d:37:8d:3f:9f:9e:89:32:ca:
+        a6:a7:e2:c8:f3:84:64:08:34:57:bd:10:22:96:78:39:b4:33:
+        dc:f2:db:83:ec:0c:20:58:ce:ba:98:44:dc:ca:a2:10:6c:5a:
+        d5:57:85:b9:3c:f0:48:99:98:e1:80:88:08:4c:cc:83:0d:40:
+        ff:8d
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----