anv: Enable SPV_INTEL_shader_integer_functions2 and VK_INTEL_shader_integer_functions2
Currently only implemented in the scalar backend, so only enable for Gen8+. If support for the other opcodes is added to the vec4 backend, Gen7 could be supported. Reviewed-by:Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com> Part-of: <mesa/mesa!767>