[SYCL] Avoid std::stable_partition to fix build with GCC 12 libstdc++
std::stable_partition can fall back to the deprecated
std::get_temporary_buffer when it fails to allocate scratch space,
which errors under -Werror -Wdeprecated-declarations with GCC 12's
libstdc++. Replace with a manual two-pass stable partition.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>