jdbc: inserted rows are still in cache after execute

[vagetablechicken]

OpenMLDB/java/openmldb-jdbc/src/main/java/com/_4paradigm/openmldb/sdk/impl/InsertPreparedStatementImpl.java

Line 361 in 90147ca

boolean ok = router.ExecuteInsert(db, currentSql, currentRows, status);

We should delete currentRows after ExecuteInsert.
So that, we can do

while:
  stmt.setXX()
  stmt.execute()

[vagetablechicken]

InsertPreparedStatementImpl problems:

1. addBatch(String s): jdbc notes that 'This method cannot be called on a PreparedStatement or CallableStatement'. We shouldn't impl it. So that, sqlRowsMap is useless.
2. sqlRowsMap: remove this.
3. addBatch(): it'll add a new row in SQLInsertRows. execute/executeBatch will do rows insertion, and delete the rows(no matter ok or failed). If SQLInsertRows.GetCnt > 1, we can force to use executeBatch.