title: Expo - Error running adb: more than one device/emulator
body: <p>I am running macOS Catalina, and have one Android emulator set up in the Android Virtual Device Manager.</p>
  <p>Before starting the emulator, on a freshly rebooted system, if I run <code>adb devices</code> I get:</p>
  <pre><code>List of devices attached
  emulator-5562   offline
  </code></pre>
  <p>After starting the emulator, <code>adb devices</code> returns:</p>
  <pre><code>List of devices attached
  emulator-5554   device
  emulator-5562   offline
  </code></pre>
  <p>If I fire up Expo and try to run on the Android emulator, I get this error:</p>
  <pre><code>Couldn't start project on Android: Error running adb: more than one device/emulator
  </code></pre>
  <p>It looks like the offline <code>emulator-5562</code> is the problem here? But it's still there even after rebooting my computer. All the advice I've read (i.e. <code>adb kill-server</code> and <code>adb restart-server</code>) makes no difference. There are no Android devices connected via USB.</p>
  <p>How can I delete the &quot;offline&quot; device? Or alternatively, how can I point Expo to the one actual Android emulator I have running?</p>