Invalid JSON for FFI objects

[kelunik]

If FFI objects are dumped, invalid JSON is generated, note the trailing comma after "2329":

    "0x7f0c227017c0" : {
        "type" : "object",
        "size" : "72",
        "symbol_name" : "Amp\\Http\\Internal\\HPackNghttp2::deflatePtrType",
        "is_root" : true,
        "frame" : "<CLASS_STATIC_MEMBER>"
,
        "class" : "FFI\\CType",
        "object_handle" : "2329",

    },

[dejagersh]

I am running into a similar problem: "Malformed UTF-8 characters, possibly incorrectly encoded "