backend: Don't process FAKE_OVERRIDE properties in lateinit lowering

backend.native/tests/codegen/lateinit/inBaseClass.kt

@@ -0,0 +1,15 @@
+class A(val a: Int)
+
+open class B {
+    lateinit var a: A
+}
+
+class C: B() {
+    fun foo() { a = A(42) }
+}
+
+fun main(args: Array<String>) {
+    val c = C()
+    c.foo()
+    println(c.a.a)
+}