This bug report was caused by implementation of the task MDEV-5816
(Stored programs: validation of stored program statements).
Changing metadata of a table that has a trigger on AFTER UPDATE or AFTER DELETE
resulted in unexpected output of the error ER_TRG_NO_SUCH_ROW_IN_TR.
It was caused by the fact that characteristics of the trigger dependent on
changed table's metadata wasn't set in a new lex object created on re-parsing
of a failing trigger statement.

To fix the bug the data member lex->trg_chistics.action_time and
lex->trg_chistics.event must be set into real values of the trigger
whose statement being re-parsed.