NPEx at InternalTriggerExecutionContext.updateAICounters

AFTER UPDATE trigger fails when the column of source table is autogenerated.

Bisected issue to fat commit a826375a (DERBY-6414). After that change NPEx is observed and update statement is forcibly prevented with current connection being closed.

Logs from example executions: at Travis, with simple SQLs available on GitHub.

Edit: as checked on more complex case, reordering columns is not enough.