[SYCL] Don't return last event in `ext_oneapi_submit_barrier` #20235

AlexeySachkov merged 2 commits intointel:sycl-rel-6_3intel/llvm:sycl-rel-6_3from

AlexeySachkov:private/asachkov/cherry-pick-20159AlexeySachkov/llvm:private/asachkov/cherry-pick-20159Copy head branch name to clipboard