* [TD-3752]<fix>: taosdemo columns+tags+ts must less then 1024. (#5782)
Co-authored-by: NShuduo Sang <sdsang@taosdata.com>

* [TD-3683]<fix>: taosdemo create lots of tables.

clean up.
Co-authored-by: NShuduo Sang <sdsang@taosdata.com>