Add sexp serialization to halide_cpp.compile
Add sexp serialization to halide_cpp.compile

Former-commit-id: 40a2fb043a95ef1200b6348bced364fd944e173c
darkbuck/Halide,Trass3r/Halide,Trass3r/Halide,darkbuck/Halide,darkbuck/Halide,darkbuck/Halide,darkbuck/Halide,Trass3r/Halide,Trass3r/Halide,Trass3r/Halide,Trass3r/Halide,Trass3r/Halide,darkbuck/Halide,darkbuck/Halide