Fix NoSuchMethodError on private components of data classes

A follow-up to
https://github.com/JetBrains/kotlin/commit/d5681540ec47ee5c9a548ba56df8b4e20097549d

compiler/testData/codegen/boxWithStdlib/dataClasses/privateValParams.kt

@@ -1,4 +1,6 @@
-data class D(private val x: Long, private val y: Char)
+data class D(private val x: Long, private val y: Char) {
+    fun foo() = "${component1()}${component2()}"
+}
 
 fun box(): String {
     val d1 = D(42L, 'a')
@@ -6,5 +8,6 @@ fun box(): String {
     if (d1 != d2) return "Fail equals"
     if (d1.hashCode() != d2.hashCode()) return "Fail hashCode"
     if (d1.toString() != d2.toString()) return "Fail toString"
+    if (d1.foo() != d2.foo()) return "Fail foo"
     return "OK"
 }