Comment 8 for bug 665669

The wrong results are triggered by an invalid value of the flag handler::in_range_check_pushed_down just before
the scan of the range pk < 2 when executing the first select query. The value of the flag is TRUE though it is expected
to be FALSE. It is FALSE because the handler is taken from the previous (EXPLAIN) command that calls
ha_innobase::idx_cond_push() setting in_range_check_pushed_down to TRUE, but never calls ha_innobase::index_end
that would reset the value of the flag back to FALSE.