[Port 2.3-develop] Don't recalculate tax for every price on category page

[JeroenVanLeusden]

Port of #15089

Description

Unnecessary recalculation of large product list pricing causes huge slowdowns.

Fixed Issues (if relevant)

1. Unnecessary recalculation of product list pricing causes huge slowdowns #14941: Unnecessary recalculation of product list pricing causes huge slowdowns

Manual testing scenarios

1. Create a catalog where prices are including tax + prices are shown including tax.
2. Go to a category page and show 100 products per page.

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)

[JeroenVanLeusden]

@miguelbalparda, can you also process the port to 2.3-develop?

[VladimirZaets]

Hi, @joachim-havloujian, I took your PR into processing, thank you for collaboration.

[VladimirZaets]

Currently, the method still returns int and bool value because $this->displayCartPricesBoth() returns bool.
Please add bool return type to doc block.

[JeroenVanLeusden]

@VladimirZaets DocBlock is updated.

[magento-engcom-team]

Hi @JeroenVanLeusden. Thank you for your contribution.
Changes from your Pull Request will be available with the upcoming 2.3.0 release.