* [TD-5398]<fix>: taosdemo 4096 columns table creation failed.

* change column name prefix from col to c for maxium column number to fix buffer length.

* use accurate buffer length.

* fix test case for column name be shorter.
Co-authored-by: NShuduo Sang <sdsang@taosdata.com>

* [TD-3401]<fix>: taosdemo query statistic.

refactor func name.

* [TD-3401]<fix>: taosdemo query statistic.

refactor func name 2.

* [TD-3401]<fix>: taosdemo support query statistic.

implementation.

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