[Backport] If stock is bellow OutOfStock Threshold, a negative qty is displayed in Product List Page

[saphaljha]

Original Pull Request

magento#19206

Description (*)

If stock is bellow OutOfStock Threshold, a negative qty is displayed in Product List Page

Fixed Issues (if relevant)

1. If stock is bellow OutOfStock Threshold, a negative qty is displayed in Product List Page magento/magento2#9130: If stock is bellow OutOfStock Threshold, a negative qty is displayed in Product List Page

Manual testing scenarios (*)

1. Set qty to 5 for a product, and Out of Stock threshold to 10. Save the product
   When browsing that product in the frontend a "Only -5 left" is displayed under "Out of Stock" message.
2. Remove the block if qty is negative.

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)