Does this break Xcode 9.4?

Sorry about the misunderstanding on the other PR, thought it was good to go.

@dnfield I don't think it does, but I'm not going to downgrade to 9.4 to test it tonight. Feel free, if you have 9.4 on a MacBook near you:

Check out this PR in a branch, then

cd some/path/
flutter create -t module --org io.flutter.add2app hello
cp -R /path/to/flutter/dev/integration_test/ios_host_app Host/
cd Host/
pod install

Now you should be able to open Host/Host.xcworkspace in Xcode and build+run it.

No apologies needed about the other PR! My bad with all the checkmarks. Anyway, it went fine on the build bots, it seems :-)