FIR2IR: Fix case of @JvmOverloads with subclass

Avoid generating synthetic overrides in subclass
It has been already working for PSI2IR because fake overrides there don't
inherit default values for parameters, while they do it in FIR

compiler/testData/codegen/box/jvmOverloads/subClass.kt

@@ -0,0 +1,15 @@
+// TARGET_BACKEND: JVM
+// WITH_RUNTIME
+
+open class A {
+    @JvmOverloads
+    fun foo(x: String, y: String = "", z: String = "K"): String {
+        return x + y + z
+    }
+}
+
+class B : A()
+
+fun box(): String {
+    return B().foo("O")
+}