End to End tests for shared cert SSL.

This patch adds the end to end test for shared SSL. The patch also
refactors some of the existing tests to DRY up the code.

Change-Id: Ie5aee2eebf791a41cf77d41899150375f8c1b8b0

tests/endtoend/utils/config.py

@@ -55,6 +55,16 @@ class TestConfig(data_interfaces.ConfigSectionInterface):
         """IP address for wordpress origin."""
         return self.get('wordpress_origin')
 
+    @property
+    def ssl_origin(self):
+        """IP address for ssl origin."""
+        return self.get('ssl_origin')
+
+    @property
+    def run_ssl_tests(self):
+        """Flag to indicate if ssl tests should be run."""
+        return self.get_boolean('run_ssl_tests')
+
     @property
     def webpagetest_enabled(self):
         """Flag to indicate if webpagetest tests should be run."""