__name@dasherize__.component.spec.ts don't use async in spec case

[alexeagle]

From @trimeyko on September 29, 2017 13:18

Component spec file scheme is old and not consistent with spec in new app since it's not using async() in spec case, should be used by default.

component:
https://github.com/angular/devkit/blob/master/packages/schematics/angular/component/files/__path__/__name%40dasherize%40if-flat__/__name%40dasherize__.component.spec.ts

spec in new app:
https://github.com/angular/devkit/blob/master/packages/schematics/angular/application/other-files/app.component.spec.ts

Copied from original issue: angular/devkit#182