server: fix insert zero timestamp bug with prepared statement

[lysu]

What problem does this PR solve?

fixes #7501

What is changed and how it works?

in protocol layer return "types.ZeroDatetimeStr" instead of "0" to make later types.parseDatetime happy.

Check List

Tests

• Unit test
• Manual test

    mysql_stmt= mysql_stmt_init(&mysql);
    if(!mysql_stmt)
    {
        my_chk_stmt(&mysql, mysql_stmt, __LINE__);
    }

    stmt= const_cast<char *>("INSERT INTO timestamp_insert ( id, tstamp ) VALUES ( ?, ? )");
    if(mysql_stmt_prepare(mysql_stmt, stmt, strlen(stmt)))
    {
        my_chk_stmt(&mysql, mysql_stmt, __LINE__);
    }

    memset(mysql_bind_param, 0, sizeof(mysql_bind_param));
    mysql_bind_param[0].buffer_type= MYSQL_TYPE_LONG;
    mysql_bind_param[0].buffer= (char*)&id;
    mysql_bind_param[0].is_null= 0;
    mysql_bind_param[0].length= 0;
    mysql_bind_param[1].buffer_type= MYSQL_TYPE_TIMESTAMP;
    mysql_bind_param[1].buffer= &tstamp;
    mysql_bind_param[1].is_null= 0;
    mysql_bind_param[1].length= 0;
    if(mysql_stmt_bind_param(mysql_stmt, mysql_bind_param))
    {
        my_chk_stmt(&mysql, mysql_stmt, __LINE__);
    }

    tstamp.year= 0;
    tstamp.month= 0;
    tstamp.day= 0;
    tstamp.hour= 0;
    tstamp.minute= 0;
    tstamp.second= 0;
    tstamp.second_part= 0;

    if(mysql_stmt_execute(mysql_stmt))
    {
        my_chk_stmt(&mysql, mysql_stmt, __LINE__);
    }

Code changes

• impl change

Side effects

• no

Related changes

• Need to cherry-pick to the release branch
• Need to be included in the release note

---

This change is 

[lysu]

/run-all-tests

[shenli]

Use a constant.

[shenli]

ditto

[jackysp]

Why not add a case for types.parseDatetime?

[lysu]

@jackysp we don't modify that, I think modified ut cover first half part, and add a second half part integration test using 'prepare s from '....'' to re-display and show fix result is enough

[jackysp]

LGTM

Need another LGTM

[imtbkcat]

LGTM

[imtbkcat]

/run-all-tests