Allow testapp to run in parallel on WIN32
Allow testapp to run in parallel on WIN32

Update how testapp launches memcached to allow it to use a automatically
assigned port number instead of hardcoding 11211. This allows multiple
testapp instances (i.e. plain and SSL) to run in parallel, along with all
the other tests.

As a consequence this significantly speeds up the WIN32 "make test"
runtime - halving it on a 2 CPU Windows VM.

Change-Id: I5ae7d732b29f6c08fe72e85487b2770f07dc1831
Reviewed-on: http://review.couchbase.org/46637
Reviewed-by: Trond Norbye <60edd2ef23891a753f231b0c6f161dc634079a93@gmail.com>
Tested-by: buildbot <80754af91bfb6d1073585b046fe0a474ce868509@couchbase.com>

cloudrain21/memcached-1,couchbase/memcached,cloudrain21/memcached-1,daverigby/kv_engine,mrkwse/memcached,mrkwse/memcached,daverigby/kv_engine,owendCB/memcached,daverigby/kv_engine,owendCB/memcached,daverigby/memcached,couchbase/memcached,owendCB/memcached,daverigby/memcached,cloudrain21/memcached-1,couchbase/memcached,daverigby/memcached,owendCB/memcached,couchbase/memcached,daverigby/kv_engine,mrkwse/memcached,cloudrain21/memcached-1,mrkwse/memcached,daverigby/memcached