Synchronously executes a subprocess, waiting for it to finish and collecting all of its output. Will throw an error if stdin: "piped" is passed.

const { status, stdout, stderr } = Deno.spawnSync(Deno.execPath(), {
  args: [
    "eval",
      "console.log('hello'); console.error('world')",
  ],
});
console.assert(status.code === 0);
console.assert("hello\n" === new TextDecoder().decode(stdout));
console.assert("world\n" === new TextDecoder().decode(stderr));