Allocate UniformDataDefaults and fill in the data defaults when
linking a SPIR-V program. Among other things, this allows program
serialization to work.
It allows the following piglit test (when run on SPIR-V mode) to pass:
spec/arb_get_program_binary/execution/uniform-after-restore.shader_test
v2: use memcpy to initialize UniformDataDefaults
Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
637b168470