[YSQL] Secondary index read does not use a consistent read point.

[robertpang]

In YBCIndexExecuteSelect(), the YBC select statement to fetch the row from the base table using the ybctid is not created with a read point:

HeapTuple
YBCIndexExecuteSelect(Relation relation, Datum ybctid)
{
    YBCPgStatement ybc_stmt;
    TupleDesc      tupdesc = RelationGetDescr(relation);

    HandleYBStatus(YBCPgNewSelect(ybc_pg_session,
                                  YBCGetDatabaseOid(relation),
                                  RelationGetRelid(relation),
                                  InvalidOid,
                                  &ybc_stmt,
                                  NULL /* read_time */));
...
}

Without the read point, the index select may not be reading the rows from the base table with a consistent read point.

[ndeodhar]

@spolitov @nocaway The code fixes for #1894 and #1611 should take care of this, right? Can I close this?

[nocaway]

@ndeodhar This has been fixed.

[kmuthukk]

Fixed as part of #1894 and #1611