[MB-11203] Enable SSL for all tests that use a socket.

Add some more focused stream/pipeline tests.

Overall increase of about 2% code coverage in memcached.c

Change-Id: Ia0b8ffbb84e53e0bd38eaf3d3641ae92161e2d92
Reviewed-on: http://review.couchbase.org/40185
Reviewed-by: Trond Norbye <trond.norbye@gmail.com>
Tested-by: Trond Norbye <trond.norbye@gmail.com>