StubEmitter doesn't handle synthetic params properly
StubEmitter doesn't handle synthetic params properly

Should filter them out when building the lists (rather than processing
them), otherwise assertions about the list being empty (or not) can be
wrong.

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