Add emit-with-commas helper
Add emit-with-commas helper

kgnk/Halide,psuriana/Halide,kgnk/Halide,psuriana/Halide,psuriana/Halide,kgnk/Halide,kgnk/Halide,kgnk/Halide,psuriana/Halide,psuriana/Halide,psuriana/Halide,kgnk/Halide,kgnk/Halide,kgnk/Halide,psuriana/Halide