[SYCL] Fix unused variable warning detected by post-commit tests

[dm-vodopyanov]

No description provided.

[dm-vodopyanov]

Add missing include

I didn't add <algorithm> explicitly, because it covers by <regex> both for Linux and Windows:

https://godbolt.org/z/qxhzMrn7o

[bader]

Add missing include

I didn't add explicitly, because it covers by both for Linux and Windows:

https://godbolt.org/z/qxhzMrn7o

Does C++ spec requires regex to include algorithm implicitly?

[dm-vodopyanov]

Does C++ spec requires regex to include algorithm implicitly?

Fair enough, these are implementation details.