Extract `get_test_queue()` function into separate file

[SergeyKopienko]

This will result in bigger changes I think, but can we resolve this dependency issue? Either in this PR or in another.

It seems like perhaps get_dpcpp_test_policy(), and perhaps some of the other utilities belong in utils_sycl.h, and maybe all the Test*Buffers calls belong here in utils_invoke.h...

Hopefully we can let utils_invoke.h include utils_sycl.h and have no dependencies in the other direction. (or some similar alternative which does not require the includer to also include the other).

Originally posted by @danhoeflinger in #2282 (comment)