If a stored function or a trigger was killed it had aborted but no error
was thrown. This allows the caller statement to continue without a notice.
This may lead to a wrong data being inserted/updated to/deleted as in such
cases the correct result of a stored function isn't guaranteed. In the case
of triggers it allows the caller statement to ignore kill signal and to
waste time because of re-evaluation of triggers that always will fail
because thd->killed flag is still on.

Now the Item_func_sp::execute() and the sp_head::execute_trigger() functions
check whether a function or a trigger were killed during execution and
throws an appropriate error if so.
Now the fill_record() function stops filling record if an error was reported
through thd->net.report_error.