txn_types: Check overflow in timestamp computation (#9777)
txn_types: Check overflow in timestamp computation (#9777)

* txn_types: Check overflow in timestamp computation

Signed-off-by: Zijie Lu <wslzj40@gmail.com>

* use assert to check overflow

Signed-off-by: Zijie Lu <wslzj40@gmail.com>

* Fix test

Signed-off-by: Zijie Lu <wslzj40@gmail.com>

* Address review comments

Signed-off-by: Zijie Lu <wslzj40@gmail.com>

Co-authored-by: Ti Chi Robot <72214b26dd6f24c8c411751e1f8e05856122286e@users.noreply.github.com>
c4pt0r/tikv,BusyJay/tikv,BusyJay/tikv,BusyJay/tikv,BusyJay/tikv