The usage of `__kernel_name_generator` without `_ExecutionPolicy`

[SergeyKopienko]

The usage of __kernel_name_generator without _ExecutionPolicy is error-prone
at:

oneDPL/include/oneapi/dpl/pstl/hetero/dpcpp/parallel_backend_sycl.h

Line 244 in a045eac

using _GroupScanKernel = oneapi::dpl::__par_backend_hetero::__internal::__kernel_name_generator<

[SergeyKopienko]

I am going to fix this issue in the PR #2161