[TD-3921] <fix>  fix the case for new python connector

Master

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

[TD-4005]<fix>: fix repeated vnode open when tsdb state not ok

[TD-4037]<test>: add taodemo-testcase that childtable_count is less and equal  to zero and num_of_records_per_req is equal to zero

Fix/td 3747

[TD-4037]<test>: add taodemo-testcase that childtable_count is less than or equal zero and num_of_records_per_req  is  equal zero

[TD-4059]update case version.py

[TD-3990]remove travis

* [TD-4035]<fix>: taosdemo more checking for prevent value out of scope.

* [TD-4035]<fix>: taosdemo more checking for prevent value out of scope.

change min rows and max rows to unsigned int and 0 means default.

* [TD-4035]<fix>: taosdemo more checking for prevent value out of scope.

change offset=0 to get all childtable count
Co-authored-by: NShuduo Sang <sdsang@taosdata.com>

[TD-3998]<test>: add taodemo-testcase that inserting  too many rows  won't make  ts  disorder 

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

[TD-4056]<fix>: fix possible char string buffer length overflow

* [TD-3976]<fix>: taosdemo print each insert performance data.

* [TD-3976]<fix>: taosdemo print insert performance per thread.
Co-authored-by: NShuduo Sang <sdsang@taosdata.com>

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