Before this PR, we were somewhat able to eliminate dead typeof checks such as:

```csharp
if (someType == typeof(Foo)
{
    ExpensiveMethod();
}
```

This work was done in dotnet#102248.

However, the optimization only happened during codegen. This meant that when building the whole program view, we'd still look at `ExpensiveMethod` and whatever damage this caused to the whole program view was permanent.

With this PR, the scanner now becomes aware of the optimization we do during codegen and tries to defer injecting dependencies until we will need them.

With this change, we detect the conditional branch, and generate whatever dependencies from the basic block as conditional. That way scanning can fully skip scanning `ExpensiveMethod` and the subsequent optimization will ensure the missed scanning will not cause issues at codegen time.