Test suspend/resume

Press "Start" button to start the test using a single oscillator.

Then press "Suspend" or "Resume" buttons as desired. "Suspend" should stop the audio. "Resume" should resume the audio immediately.

Some tests to run:

• Suspend/Resume Test
  1. Press "Start test"; audio should be heard.
  2. Press "Suspend" multiple times. The first press should stop the audio. Each subsequent press should do nothing, but the console should show that each press is resolved successfully.
  3. Press "Resume". The first press should resume audio immediately. Each subsequent press should do nothing, but the console should show that each press is resolved successfully.
  4. Press "Stop test" to stop the test; audio should stop.
• Closed Test
  1. Press "Start test"; audio should be heard.
  2. Press "Stop test"; audio should stop
  3. Press "Suspend" or "Resume". Each press should result in a rejected promise immediately with an error that suspend or resume is invalid on a closed context.

See issue 476429