* cherry pick from develop branch.

* [TD-5136]<feature>: taosdemo simulate real senario.

* update test case according to taosdemo change

* adjust range of semi-random data.

* make demo mode use different tag name and value.

* change malloc to calloc for pid allocation.

* fix typo.
Co-authored-by: NShuduo Sang <sdsang@taosdata.com>