DPC++ daily 2023-01-03

[SYCL] More adjustments for SYCL 2020 vec aliases (#7896)

This is a follow-up from intel/llvm#7889. Adjusted LIT tests to account
for the new definition of `long{n}` alias, which may not always be equal
to `sycl::vec<long, n>` now. Removed some dead code (type traits) from the
runtime.