message: refactor(forms): replace instanceof Array
  PR Close
diff: @@ -47,10 +47,10 @@ export const DISABLED = 'DISABLED';
  function _find(control: AbstractControl, path: Array<string|number>| string, delimiter: string) {
  if (path == null) return null;
  - if (!(path instanceof Array)) {
  + if (!Array.isArray(path)) {
  path = path.split(delimiter);
  }
  - if (path instanceof Array && path.length === 0) return null;
  + if (Array.isArray(path) && path.length === 0) return null;
  return path.reduce((v: AbstractControl | null, name) => {
  if (v instanceof FormGroup) {
  