Refactor sort_by_key tests to reuse common test framework

[dmitriy-sobolev]

Summary: sort_by_key.pass and stable_sort_by_key.pass tests are not aligned with the majority of other tests. That is, they do not rely on the utilities from the oneDPL testing framework, such as invoke_on_all_host_policies.

Using the utilities may simplify the tests and expand their coverage.

The issue was motivated by discussion: https://github.com/oneapi-src/oneDPL/pull/1692#discussion_r1701557694.

Preferred Solution: Adapt the tests to use invoke_on_all_host_policies.