Fails to initialize when no objc runtime found

[trufae]

The 19034 pid corresponds to a cat

$ r2 frida://19034
Unhandled message: {"type":"error","description":"TypeError: Cannot read property 'class' of undefined","stack":"TypeError: Cannot read property 'class' of undefined\n    at registerTypes (../../node_modules/mjolner/lib/objc.js:86:25)\n    at Object.register (../../node_modules/mjolner/lib/objc.js:32:7)\n    at Object.register (../../node_modules/mjolner/index.js:10:10)\n    at Object.<anonymous> (index.js:421:9)\n    at Object.8.mjolner (r2io.js:2518:4)\n    at s (../../node_modules/browser-pack/_prelude.js:1:1)\n    at e (../../node_modules/browser-pack/_prelude.js:1:1)\n    at ../../node_modules/browser-pack/_prelude.js:1:1","fileName":"../../node_modules/mjolner/lib/objc.js","lineNumber":86,"columnNumber":25}
^C