BUGFIX for issue #1161

[jonnylink]

This is:

- [x] a bugfix (#1161)
- [ ] a new feature

Checklist:

• Changes are covered by unit tests — No. Removed code that was never covered in tests and shouldn't have been there in the first place. Nothing to test.
• 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 — no not necessary

Why this change is needed?

As noted in #1161 there was some test code left in the calculation.php file. This would only show up on larger files, so it hasn't been prevalent, but it should be removed. There are no references to the constants being set. Even if they were, it's bad practice to set constants in code. Here it's in a loop and also in a simple if/else block.

[mostafatalebi]

May I know when we are going to have this commit released? (it is merged with master but not release-tagged).

[PowerKiKi]

That was released in https://github.com/PHPOffice/PhpSpreadsheet/releases/tag/1.11.0 back in March.