[FIR2IR] Properly calculate the type of delegated function call

```
interface A {
    fun <T> foo(): T
}

class B(val a: A) : A by A {
    generated fun <T'> foo(): T' {
        return a.foo() // <------
    }
}
```

There was a problem that type of generated delegated call used
  an unsubstituted type of the original delegated declaration, which led
  to a situation when (see example) type of call `a.foo()` was not `T'`
  but `T`, which led to incorrect IR and further exceptions on backend

^KT-64257 Fixed
^KT-64284 Obsolete

compiler/testData/codegen/box/delegation/genericFunctionInGenericInterface.kt

@@ -0,0 +1,15 @@
+// ISSUE: KT-64257
+
+interface Base {
+    fun <R> fold(initial: R, operation: (R, String) -> R): R = operation(initial, "K")
+}
+
+interface Derived<T> : Base
+
+class Impl<T> : Derived<T>
+
+fun box(): String {
+    val impl = Impl<String>()
+    val delegated = object : Derived<String> by impl {}
+    return delegated.fold("O") { a, b -> a + b }
+}