Xcode 10 seems to break com.apple.commcenter.coretelephony.xpc

Running this in Terminal made it go away:

xcrun simctl spawn booted log config --mode "level:off"  --subsystem com.apple.CoreTelephony

Well it's working on both the simulator and device in Xcode 10.2.

1. Add CoreTelephony.framework (Optional)

2. Executing the following command in Terminal:

   xcrun simctl spawn booted log config --mode "level:off" --subsystem 
   com.apple.CoreTelephony
   

3. From the Xcode menu open: Product > Scheme > Edit Scheme

   On your Environment Variables set OS_ACTIVITY_MODE = disable

4. Restart simulator