Upstream AP Intel extensions

Upstream AP Intel extensions

SPV_INTEL_arbitrary_precision_floating_point and
SPV_INTEL_arbitrary_precision_fixed_point extensions are
being upstreamed.

Specs:
https://github.com/intel/llvm/blob/2f6e965e686354fbb25f9c177a667a646de302eb/sycl/doc/extensions/SPIRV/SPV_INTEL_arbitrary_precision_fixed_point.asciidoc
https://github.com/intel/llvm/blob/bd86b218f749ea0e20ddc18c42db491faf54014a/sycl/doc/extensions/SPIRV/SPV_INTEL_arbitrary_precision_floating_point.asciidoc

Signed-off-by: Dmitry Sidorov <dmitry.sidorov@intel.com>