IR: get overridden directly from IrProperty when resolving fake override

The previous way of getting them either via getter or setter failed on
Java properties which only have a backing field. Now that IrProperty has
overriddenSymbols (after 53c1de172f), it makes sense to use it directly
instead. Use it only in SyntheticAccessorLowering though to avoid
breaking Kotlin/Native (see KT-47019).

 #KT-46900 Fixed

compiler/testData/codegen/box/syntheticAccessors/protectedJavaFieldAccessor/kt46900_jkk_inheritance.kt

@@ -0,0 +1,20 @@
+// TARGET_BACKEND: JVM
+// FILE: Base.java
+
+import org.jetbrains.annotations.NotNull;
+
+public abstract class Base {
+    @NotNull
+    protected String result = "OK";
+}
+
+// FILE: Derived.kt
+
+open class Mid : Base()
+
+class Derived : Mid() {
+    fun foo(): String =
+        (Derived::result)(this)
+}
+
+fun box(): String = Derived().foo()