Fix exact MATCH on ranges with empty cells

[arnested]

This is:

- [x] a bugfix
- [ ] a new feature

Checklist:

• Changes are covered by unit tests
• Code style is respected
• Commit message explains why the change is made (see https://github.com/erlang/otp/wiki/Writing-good-commit-messages)
• CHANGELOG.md contains a short summary of the change
• Documentation is updated as necessary

Why this change is needed?

Fixes a bug when doing exact match on ranges with empty cells.

<?php

require 'vendor/autoload.php';

use PhpOffice\PhpSpreadsheet\Spreadsheet;

$spreadsheet = new Spreadsheet();
$sheet = $spreadsheet->getActiveSheet();

// Row: 1, null, 4, null, 8.
$sheet->getCell('A1')->setValue(1);
$sheet->getCell('A3')->setValue(4);
$sheet->getCell('A5')->setValue(8);

$sheet->getCell('B1')->setValue('=MATCH(4, A1:A5, 1)');

// Should echo 3, but echos '#N/A'.
echo $sheet->getCell('B1')->getCalculatedValue() . PHP_EOL;

// Row: 1, null, 4, null, null.
$sheet->getCell('C1')->setValue(1);
$sheet->getCell('C3')->setValue(4);

$sheet->getCell('D1')->setValue('=MATCH(5, C1:C5, 1)');

// Should echo 3, but echos '#N/A'.
echo $sheet->getCell('D1')->getCalculatedValue() . PHP_EOL;

Before fix:

#N/A
#N/A

After fix:

3
3

[MarkBaker]

Thank you for this fix. This (and your other MATCH fix) weren't cases that we considered when we're developing the original code logic to implement MATCH()