Locked rows of the InnoDB storage was silently skipped in the read-committed
isolation level.

QUICK_RANGE_SELECT for unique ranges lacks second (blocking) read
of the record that was read semi-consistently and just skip it.

The handler::read_multi_range_next method has been modified
to retry previous unique range if the previous read was
semi-consistent.


sql/handler.cc:
  Fixed bug #31310.
  The handler::read_multi_range_next method has been modified
  to retry previous unique range if the previous read was
  semi-consistent.
mysql-test/include/mix1.inc:
  Added test case for bug #31310.
mysql-test/r/innodb_mysql.result:
  Added test case for bug #31310.