1. Add missing lock / unlock in profiling code. Without
   synchronization, the profiling code could access freed memory.
2. Remove unnecessary assert.
3. Remove unncessary if check in taosHashRemoveWithData.

* Testing
sample mysql:
taos> create database db;
Query OK, 0 of 0 row(s) in database (0.002291s)

taos> use db;
Query OK, 0 of 0 row(s) in database (0.000197s)

taos> create table t (ts timestamp, a int);
Query OK, 0 of 0 row(s) in database (0.003851s)

taos> insert into t values ('2019-07-15 00:00:00', 1);
Query OK, 1 of 1 row(s) in database (0.001128s)

taos> insert into t values ('2019-07-15 01:00:00', 2);
Query OK, 1 of 1 row(s) in database (0.000249s)

taos> select * from t;
           ts            |      a      |
========================================
 2019-07-15 00:00:00.000 |           1 |
 2019-07-15 01:00:00.000 |           2 |
Query OK, 2 row(s) in set (0.000772s)

taos> drop database db;
Query OK, 0 of 0 row(s) in database (0.002308s)