Add sycl headers to bazel toolchain config for DPCPP through icx

[david-cortes-intel]

Description

There is a step in the bazel test pipeline for //cpp/oneapi/dal:tests in which it probes the compiler for include paths of headers to add to the toolchain config:

oneDAL/dev/bazel/toolchains/cc_toolchain_lnx.bzl

Line 103 in b6b6a65

def _preapre_builtin_include_directory_paths(repo_ctx, tools):

It does so by requesting the default paths from the compiler with this command:

<compiler> -E -xc++ - -v

In the case of DPCPP, this resolves to:

icx -E -xc++ - -v

By default, icx doesn't include sycl linkage, thus the command above does not return the paths of SYCL headers. Under the default icx factory settings, that leads to observing an error:

the source file 'cpp/oneapi/dal/algo/pca/test/serialization.cpp' includes the following non-builtin files with absolute paths (if these are builtin files, make sure these paths are in your toolchain):
  '/opt/intel/oneapi/compiler/2024.2/include/sycl/sycl.hpp'

This PR should address it by adding the necessary -fsycl flag when probing the compiler for its header paths.

[Alexandr-Solovev]

/intelci: run

[Alexandr-Solovev]

Overall looks good to me, I started private ci job with extended number of test cases via /intelci:run , lets wait the private job before merging