[test] Adds 'hello world' screenshot test

This CL is the initial commit for a screenshot test. A further CL will
provide tooling for updating the goldens.

Bug: 1051458
Change-Id: Id61dd0a804ad33566451e0f56f6981e3e7bd9067
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/2051984
Commit-Queue: Paul Lewis <[email protected]>
Reviewed-by: Tim van der Lippe <[email protected]>
diff --git a/test/shared/rimraf.d.ts b/test/shared/rimraf.d.ts
new file mode 100644
index 0000000..607a3a8
--- /dev/null
+++ b/test/shared/rimraf.d.ts
@@ -0,0 +1,7 @@
+// Copyright 2020 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+declare module 'rimraf' {
+  export function sync(path: string): void;
+}