MB-20771: Remove unnecessary defragmenter_test operator overloads
MB-20771: Remove unnecessary defragmenter_test operator overloads

The defragmenter test has it's own operator new/delete overload, to
improve interopability with Valgrind (so Valgrind saw explicit calls our
malloc / free).

However the global_new_replacement in platform does this anyway now, so
this code is no longer needed.

Change-Id: Iadebd763e4cbff7399ceb82071a402a5e696e91d
Reviewed-on: http://review.couchbase.org/67305
Well-Formed: buildbot <80754af91bfb6d1073585b046fe0a474ce868509@couchbase.com>
Tested-by: buildbot <80754af91bfb6d1073585b046fe0a474ce868509@couchbase.com>
Reviewed-by: Trond Norbye <60edd2ef23891a753f231b0c6f161dc634079a93@gmail.com>

daverigby/memcached,couchbase/memcached,couchbase/memcached,daverigby/kv_engine,couchbase/memcached,daverigby/kv_engine,daverigby/kv_engine,couchbase/memcached,daverigby/memcached,daverigby/kv_engine,daverigby/memcached,daverigby/memcached