title: react-native run-ios can not find any simulator
body: <p>I have been facing an issue where 'react-native run-ios' can not start, regardless of the simulator I add to the --simulator argument.
  XCode has the correct location for the 'command line tools'</p>
  
  <p>I am always getting the error:
  Could not find iPhone X simulator</p>
  
  <pre><code>Error: Could not find iPhone X simulator
      at resolve (/Users/eric/.../swim/node_modules/react-native/local-cli/runIOS/runIOS.js:149:13)
      at new Promise (&lt;anonymous&gt;)
      at runOnSimulator (/Users/eric/.../swim/node_modules/react-native/local-cli/runIOS/runIOS.js:134:10)
      at Object.runIOS [as func] (/Users/eric/.../swim/node_modules/react-native/local-cli/runIOS/runIOS.js:106:12)
      at Promise.resolve.then (/Users/eric/.../swim/node_modules/react-native/local-cli/cliEntry.js:117:22)
  </code></pre>
  
  <p>react-native info</p>
  
  <pre><code>&gt;   React Native Environment Info:
  &gt;     System:
  &gt;       OS: macOS 10.14.2
  &gt;       CPU: (12) x64 Intel(R) Core(TM) i9-8950HK CPU @ 2.90GHz
  &gt;       Memory: 6.76 GB / 32.00 GB
  &gt;       Shell: 3.2.57 - /bin/bash
  &gt;     Binaries:
  &gt;       Node: 10.15.0 - /usr/local/bin/node
  &gt;       Yarn: 1.13.0 - /usr/local/bin/yarn
  &gt;       npm: 6.4.1 - /usr/local/bin/npm
  &gt;     SDKs:
  &gt;       iOS SDK:
  &gt;         Platforms: iOS 12.1, macOS 10.14, tvOS 12.1, watchOS 5.1
  &gt;     IDEs:
  &gt;       Android Studio: 3.1 AI-173.4819257
  &gt;       Xcode: 10.1/10B61 - /usr/bin/xcodebuild
  &gt;     npmPackages:
  &gt;       react: 16.6.3 =&gt; 16.6.3 
  &gt;       react-native: 0.57.8 =&gt; 0.57.8 
  &gt;     npmGlobalPackages:
  &gt;       create-react-native-app: 1.0.0
  &gt;       react-native-cli: 2.0.1
  &gt;       react-native-git-upgrade: 0.2.7
  </code></pre>