Revert "rra/zhelenskiy/flattening_impl"

This reverts commit b7f5c039a6.

compiler/testData/codegen/box/valueClasses/mfvcFieldInitializationOrder.kt

@@ -1,27 +0,0 @@
-// WITH_STDLIB
-// TARGET_BACKEND: JVM_IR
-// WORKS_WHEN_VALUE_CLASS
-// LANGUAGE: +ValueClasses
-// CHECK_BYTECODE_LISTING
-
-@JvmInline
-value class DPoint(val x: Double, val y: Double)
-
-class A(var x: DPoint) {
-    init { x = DPoint(2.0, 3.0) }
-}
-
-class B() {
-    var a = DPoint(4.0, 5.0)
-    val b = a
-    init { a = DPoint(6.0, 7.0) }
-    val c = a
-}
-
-fun box(): String {
-    require(A(DPoint(0.0, 1.0)).x == DPoint(2.0, 3.0)) { "No init used" }
-    require(B().a == DPoint(6.0, 7.0)) { "No init used" }
-    require(B().b == DPoint(4.0, 5.0)) { "Wrong init order used" }
-    require(B().c == DPoint(6.0, 7.0)) { "Wrong init order used" }
-    return "OK"
-}