[SYCL] Make `core.hpp` independent from `sub_group.hpp`#16044

againull merged 4 commits intointel:syclintel/llvm:syclfrom

AlexeySachkov:private/asachkov/dont-include-sub-group-hppAlexeySachkov/llvm:private/asachkov/dont-include-sub-group-hppCopy head branch name to clipboard