[FIR2IR] Fix handling private setters in anonymous classes

^KT-65290 Fixed

compiler/testData/codegen/box/fakeOverride/fakeOverrideOfPrivateSetter.kt

@@ -0,0 +1,11 @@
+// JVM_ABI_K1_K2_DIFF: KT-63984
+
+abstract class TextRendererActions1 {
+    var fontSize: String = "OK"; private set
+}
+
+fun box() : String {
+    return object : TextRendererActions1() {
+        val glyph = this.fontSize
+    }.glyph
+}