Refactor: migrate testapp to nlohmann::json [9/n]
Refactor: migrate testapp to nlohmann::json [9/n]

Use nlohmann::json in testapp_tests.cc

Change-Id: I3b48c3a1ff385487f602a0399fe5c3b0b7a43430
Reviewed-on: http://review.couchbase.org/101029
Tested-by: Build Bot <80754af91bfb6d1073585b046fe0a474ce868509@couchbase.com>
Reviewed-by: Dave Rigby <a09264da4832c7ff1d3bf1608a19f4b870f93750@couchbase.com>

daverigby/kv_engine,daverigby/kv_engine,daverigby/kv_engine,daverigby/kv_engine