FIX BUGS:
[TD-1389]: update query null value test
[TD-]: fix timestamp precision description
[TD-1248]: fix crash in tcache.c
[TD-1341]: Fix link and runtime errors in vs2019 compilation environment
[TD-1224]: Repair the possibility of table uid duplication
[TD-1303]: The timestamp display incorrectly when the show connecions statement is executed
[TD-1310]: Fix some defects of mqtt module
[TD-1323]: Allow no port number for the ”first“ configuration item
[TD-1354]: Monitor is no longer executed in the timer thread
[TD-1299]: crash when not using default tag order
[TD-1252]: Alert reports result type is not bool
[TD-1309]: comparation of incompatible types should raise an error
[TD-1039]: query 'select database()' return result like mysql
[TD-1407]:  fix an issue coverity reports

NEW FEATURES:
[TD-1230]: last_row function supports time range filtering，and this time filter works as expected.
[TD-934]: Distinguish between invalid error and sql syntax error

ENHANCEMENTS:
[TD-1370]: support function count(1)

TEST:
[TD-1290] add test case for group by
[TD-1320] add test case - insert data with tag specified
[TD-1360]: add test case - read binary data using Java
[TD-1389]: update query null value test