Repurpose Kokkos_ARCH_INTEL_GEN for SYCL to mean JIT to be conforming with OMPT

[masterleinad]

Currently, Kokkos_ARCH_INTEL_GEN is used for SYCL to compile AOT for all architectures from Gen9 on which is pretty useless and will not even succeed since not all features used are supported for all architectures. For OpenMPTarget, we don't have AOT flags (but we should likely just use the ones we have for SYCL already) but I was told that Kokkos_ARCH_INTEL_GEN means JIT compilation.
This pull request repurposes Kokkos_ARCH_INTEL_GEN for SYCL to also mean JIT compilation to facilitate switching between SYCL and OMPT in a consistent way with respect to architecture flags.

Documentation:

• https://www.intel.com/content/www/us/en/develop/documentation/oneapi-dpcpp-cpp-compiler-dev-guide-and-reference/top/compiler-reference/compiler-options/compiler-option-details/offload-openmp-and-parallel-processing-options/fsycl-targets.html
• https://www.intel.com/content/www/us/en/develop/documentation/oneapi-dpcpp-cpp-compiler-dev-guide-and-reference/top/compiler-reference/compiler-options/compiler-option-details/offload-openmp-and-parallel-processing-options/fopenmp-targets-qopenmp-targets.html

[zippylab]

This would be helpful for Aurora apps development using Kokkos. The logic for OMPT to specify various AoT targets could then be just the same (as it has almost been in locally-modified kokkos_arch.cmake files for OMPT. Explicitly putting in the -fsycl-targets=spir64 (and -fopenmp-targets=spir64 as has been done locally for OMPT) would help make it transparent that JIT is to be used.