Fix initialization of object's INSTANCE$ field

Call object's constructor in <clinit> and ignore the result, but in the first
line of <init> save the current "this" to INSTANCE$

 #KT-4516 Fixed
 #KT-4543 Fixed
 #KT-5291 Fixed
 #KT-5523 Fixed
 #KT-5582 Fixed

compiler/testData/codegen/box/objects/objectInitialization_kt5523.kt

@@ -0,0 +1,6 @@
+object A {
+    val a = "OK"
+    val b = A.a
+}
+
+fun box() = A.b