args do not support uint64

[zhixinwen]

Issue description

We upgrade the driver from 1.4.1 to 1.5, and all the select statements with uint64 as args are failing.

I think the issue is introduced by #838., which would fail https://github.com/golang/go/blob/master/src/database/sql/convert.go#L83.

For

	var err error
	arg := nv.Value
	nv.Value, err = c.cci.ColumnConverter(index).ConvertValue(arg)
	if err != nil {
		return err
	}
	if !driver.IsValue(nv.Value) {
		return fmt.Errorf("driver ColumnConverter error converted %T to unsupported type %T", arg, nv.Value)
	}
	return nil

In 1.4, nv.Value would be casted to int64, so driver.IsValue returns true. Now, nv.Value would remainuint64, and driver.IsValue would return false, and cause the error above.

Error log

converting argument $1 type: driver ColumnConverter error converted uint64 to unsupported type uint64"```

### Configuration
*Driver version (or git SHA):*
1.5
*Go version:* run `go version` in your console
go version go1.14.2 darwin/amd64

[zhixinwen]

We are using https://github.com/luna-duclos/instrumentedsql for instrumentation, and I notice this error only occurs when we use it combined with driver version 1.5.

I am feeling the combination triggers the call path above, and that is why many people do not see the error before..

[zhixinwen]

In instrumentedsql it checks is mysqlStmt implements driver.NamedValueChecker, since it does not implement driver.NamedValueChecker it would use ccChecker.CheckNamedValue. And this code path changes triggers the bug.

If no instrument is used, it would fall back to driver.NamedValueChecker in mysqlConn

[zhixinwen]

send out a fix in #1090

[cristaloleg]

Looks like it can be closed.

[zhixinwen]

Can we please cut a release for the patch? We still accidentally get upgraded.

[kavimehta]

+1 This bug has caused issues for my team. Cutting a new release would be great