HLOperationLower: generate new DXIL op from old HL ops.

[tex3d]

HLOperationLower: generate new DXIL op from old HL ops. Test that old HLSL intrinsics produce new DXIL barrier op after lowering, regardless of shader model. Without deprecation of the old barrier op, this is lower priority and can be done later. However, execution coverage for the new barrier DXIL op will likely suffer as a result.