DPC++ daily 2022-09-21

[SYCL][NFC] Reintroduce missing Windows symbols (#6830)

https://github.com/intel/llvm/pull/6685 unintentionally caused the
windows library to lose symbols for handler::verifyKernelInvoc and
handler::is_host. This patch introduces these as unused members to avoid
the patch being ABI-breaking.

Signed-off-by: Larsen, Steffen <steffen.larsen@intel.com>