Xcode 升级10.3 版本后模拟器消失

Xcode 升级 10.3 版本后所有的模拟器都消失了，手动添加的时候报错如下：

Invalid runtime: com.apple.CoreSimulator.SimRuntime.iOS-12-4

解决办法：
Kill all simulator processes

$ sudo killall -9 com.apple.CoreSimulator.CoreSimulatorService

Set the correct Xcode path

$ sudo xcode-select -s  /Applications/Xcode.app/Contents/Developer

If that doesn’t work, reset all simulators

$ xcrun simctl erase all