[Forwardport] [Search] Unit test for SynonymAnalyzer model

[nmalevanec]

Original Pull Request

#17801

Description

A phpunit test for the \Magento\Search\Model\SynonymAnalyzer class added

[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.
Add the comment under your pull request to deploy test or vanilla Magento instance:

• @magento-engcom-team give me test instance - deploy test instance based on PR changes
• @magento-engcom-team give me {$VERSION} instance - deploy vanilla Magento instance

For more details, please, review the Magento Contributor Assistant documentation

[osrecio]

I will close this PR because is Duplicated with: #17837 and we priorize the original author of PR to make a Port.

Thanks for your contribution.