FIR: Preserve K1 behavior for synthetic properties on raw type

^KT-54502 Fixed

compiler/testData/diagnostics/tests/platformTypes/rawTypes/rawTypeSyntheticExtensions.kt

@@ -0,0 +1,24 @@
+// SKIP_TXT
+// FIR_IDENTICAL
+// FILE: Generic.java
+import java.util.List;
+
+public class Generic<T extends Generic> {
+    // Returns Raw type
+    public static Generic create() { return null; }
+    public List<String> getFoo() { return null; }
+
+    public T getChild() { return null; }
+    public List<Generic> getChildren() { return null; }
+}
+
+// FILE: main.kt
+fun main() {
+    val generic = Generic.create() // has a type of Generic<(raw) Any..Any?>
+
+    generic.getFoo() // has return type List<(raw) Any..Any?>
+    generic.getFoo()[0].<!UNRESOLVED_REFERENCE!>length<!> // Unresolved "length"
+    generic.foo[0].length // OK
+
+    generic.child.children[0].foo[0].length // OK
+}