Merge branch '521197-add-specs-for-testing-search-keeps-existing-charset' into 'master'

Add tests for search highlight and truncate with non-ASCII chars

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/182595



Merged-by: Terri Chu <tchu@gitlab.com>
Approved-by: Meir Benayoun <mbenayoun@gitlab.com>
Approved-by: Nikola Milojevic <nmilojevic@gitlab.com>
Reviewed-by: Meir Benayoun <mbenayoun@gitlab.com>