[Forwardport] Replace floatval() function by using direct type casting to (float)

[nmalevanec]

Original Pull Request

#16848

Description

Direct type casting is up to 6x faster than using casting functions like floatval(). So this pull request replaces the floatval() functions by direct type casting to (float).

Similar PR:

#16422 Replace intval() function by using direct type casting to (int) where no default value is needed

Contribution checklist

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with unit/integration tests (if applicable)
• All automated tests passed successfully (all builds on Travis CI are green)

[magento-engcom-team]

Hi @nmalevanec. Thank you for your contribution
Here is some useful tips how you can test your changes using Magento test environment.
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[magento-engcom-team]

Hi @ihor-sviziev, thank you for the review.
ENGCOM-2853 has been created to process this Pull Request

[magento-engcom-team]

Hi @nmalevanec. Thank you for your contribution.
We will aim to release these changes as part of 2.3.0.
Please check the release notes for final confirmation.