错误描述：
Description: Failed to find a suitable device for the type IBSimDeviceTypeiPad2x (com.apple.dt.Xcode.IBSimDeviceType.iPad-2x) with runtime iOS 12.4 (12.4 - 16G73) - com.apple.CoreSimulator.SimRuntime.iOS-12-4
Failure Reason: Failed to create new simulator device that matches IBSimDeviceTypeiPad2x (com.apple.dt.Xcode.IBSimDeviceType.iPad-2x) for runtime iOS 12.4 (12.4 - 16G73) - com.apple.CoreSimulator.SimRuntime.iOS-12-4 (Invalid runtime: com.apple.CoreSimulator.SimRuntime.iOS-12-4)
Underlying Errors:
Description: Invalid runtime: com.apple.CoreSimulator.SimRuntime.iOS-12-4
解决：
①杀死所有的simulator进程
$ sudo killall -9 com.apple.CoreSimulator.CoreSimulatorService
②设置正确的xcode路径
$ sudo xcode-select -s /Applications/Xcode.app/Contents/Developer
③如果以上两步未起作用则重置所有simulator
$ xcrun simctl erase all
