Add value to error message when size extends

Hi all,

We have encountered an issue when executing an insert command,
when one of the values' length was bigger than the column size limitation.

the error message which been displayed was "value too long for type char..."
but there was no indication which value has exceeded the limited size.
(See bug #8880)

Attached is a WIP patch which attend to make the message clearer.

Regards,
Maor and Daniel