Rework multiple query result

[hououou]

Rework query results of multiple query statements. We use the list chain of query results for multiple query statements. To get each query result, we could loop to get each query result. Implement the following interfaces:

• toString() : return the string of the first query result.
• hasNextQueryResult(): return true if we have more query results otherwise false
• getNextQueryResult(): return the next query result

Note the query result is the result for each individual query statement.
TODO: We should expose hasNextQueryResult()``getNextQueryResult() in java/nodejs/rust/python apis.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 92.19%. Comparing base (6b1d45a) to head (570cd55).
Report is 6 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3191      +/-   ##
==========================================
- Coverage   92.19%   92.19%   -0.01%     
==========================================
  Files        1157     1156       -1     
  Lines       44010    43999      -11     
==========================================
- Hits        40576    40563      -13     
- Misses       3434     3436       +2     

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[andyfengHKU]

Add test file based e2e tests.