pThreadObj is freed when thread exits

fix test case error

fix test failures

edit fulltest.sh add testcase table/alter_wal0.py  &  edit architectu…

TD-1768

fix: docs and tests typos, taos_fetch_subfields --> taos_fetch_fields…

[TD-1758]<fix>: possible crash when insert data to two tables in one statement

Feature/query

prefer named-type rather than void-type to reduce typos

Update taosd-ch.md

[TD-1758] <test> add test case

<test> modify test case

[TD-1471]<fix>: empty result was returned if a database was dropped during query

Feature/os

Update cluster-ch.md