[TD-6264]<hotfix>:backport _block_dist() from 2.1 to 2.0 to fix core dump due to tbuf length limitation

* [TD-5811]<fix>: taosdemo use us to count delay.

to avoid very large number if the delay is 0ms.

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

* [TD-5725]<fix>: taosdump --help, regarding acceptable timestamp.

* make example date time same.

to avoid very large number if the delay is 0ms.

* [td-5654]<fix>: fix the bug caused by unexpected error code.

* [td-5707]<fix>: fix bug in interp query while only one row exists in a table.

* [TD-5702]<fix>: taosdemo remove memory operation.

* [TD-5702]<fix>: taosdemo remove memory operation.

* add remainderBufLen to check row data generation.

* row data generation with remainder buffer length checking.
Co-authored-by: NHaojun Liao <hjliao@taosdata.com>
Co-authored-by: NHaojun Liao <hjxilinx@users.noreply.github.com>
Co-authored-by: NShuduo Sang <sdsang@taosdata.com>

* [TD-3197]<fix>: taosdemo and taosdump coverity scan issues.

* exit if read sample file failed.

* fix converity scan issue.

* fix coverity scan issue.

* fix coverity scan memory leak.

* fix resource leak reported by coverity scan.
Co-authored-by: NShuduo Sang <sdsang@taosdata.com>

* [TD-5625]<fix>: taosdemo don't use printf for data generation.

* re cherry-pick

* [TD-5445]<fix>: taosdemo bug stmt interface with sample data.

sync from develop branch.

* refactoring some macros.

* fix mac compile error.