Application gets stuck on splash screen in Release config with MvvmCross 8.0.2
## 🐛 Bug Report

Application gets stuck on splash screen.

### Expected behavior

Application gets navigated to the first view model.

### Reproduction steps

Compile an iOS app with Release | iPhone configuration:
SDK Version: 15.0
Linker behavior: Link Framework SDKs Only
Supported architectures: ARMv7 + ARM64
HttpClient: Managed
Debug information: None
- [x] Strip native debugging symbols
- [x] Enable optimizations

Either publish for TestFlight or locally launch on an iPhone device.
The steps may not work on other projects.

### Configuration

**Version:** 8.0.2

**Platform:** 
- [x] :iphone: iOS
- [ ] :robot: Android
- [ ] :checkered_flag: WPF
- [ ] :earth_americas: UWP
- [ ] :apple: MacOS
- [ ] :tv: tvOS
- [ ] :monkey: Xamarin.Forms

### Comment

That started after upgrading from 6.4.2 to 8.0.2.
I also cannot debug it since with any debugging option enabled (still in Release configuration) the issue disappears.
When I tried to downgrade to 7.1.2 the issue has gone as well.

I tried to find out the cause of the issue myself and found out that `NavigateToFirstViewModel` never finishes if awaited.
If `await` is removed then the app crashes.
I could be wrong it's the key of the issue, just the maximum I could find myself.