IR: Fix inner class type parameters in IrTypeSystemContext

compiler/testData/codegen/box/innerNested/innerImplicitParameter.kt

@@ -0,0 +1,11 @@
+open class C<T> {
+    inner class A<U>(val x: T?, val y: U)
+
+    class D : C<Nothing>() {
+        fun f() = A<String>(null, "OK")
+    }
+}
+
+fun box(): String {
+    return C.D().f().y
+}