Don't checksum 1=1 on master if table on slave is too large.

lib/NibbleIterator.pm

@@ -48,7 +48,6 @@ $Data::Dumper::Quotekeys = 0;
 #   select      - Arrayref of table columns to select
 #   chunk_index - Index to use for nibbling
 #   one_nibble  - Allow one-chunk tables (default yes)
-#   where       - WHERE clause
 #   resume      - Hashref with lower_boundary and upper_boundary values
 #                 to resume nibble from
 #

lib/PerconaTest.pm

@@ -590,7 +590,7 @@ sub count_checksum_results {
          $line =~ m/$table$/m ? $line : '';
       }
    }
-   grep { m/^\d+\-\d+T/ } split /\n/, $output;
+   grep { m/^\d+\-\d+T\d\d:\d\d:\d\d\s+\d+/ } split /\n/, $output;
    my $colno = $checksum_result_col{lc $column};
    die "Invalid checksum result column: $column" unless defined $colno;
    my $total = 0;