[FIR2IR] Automatically store IR declaration in its parent upon creation

Previously, creating a declaration with Fir2IrCallableDeclarationsGenerator/
  Fir2IrClassifiersGenerator didn't guarantee that this declaration will
  be actually added to the list of parent class/file declarations, which
  lead to situations when FIR2IR created some declarations in the air
  (mostly fake-overrides)

compiler/testData/ir/irText/classes/delegatedGenericImplementation.fir.kt.txt

@@ -17,6 +17,7 @@ class Test1<E : Any?> : IBase<E> {
 
   }
 
+  private /* final field */ val $$delegate_0: IBase<E> = i
   override fun <B : Any?> foo(a: E, b: B) {
     <this>.#$$delegate_0.foo<B>(a = a, b = b)
   }
@@ -34,8 +35,6 @@ class Test1<E : Any?> : IBase<E> {
       (<this>.#$$delegate_0, <this>).<set-x><D>(<set-?> = <set-?>)
     }
 
-  private /* final field */ val $$delegate_0: IBase<E> = i
-
 }
 
 class Test2 : IBase<String> {
@@ -45,6 +44,11 @@ class Test2 : IBase<String> {
 
   }
 
+  var j: IBase<String>
+    field = j
+    get
+    set
+
   override fun <B : Any?> foo(a: String, b: B) {
     <this>.#j.foo<B>(a = a, b = b)
   }
@@ -62,9 +66,5 @@ class Test2 : IBase<String> {
       (<this>.#j, <this>).<set-x><D>(<set-?> = <set-?>)
     }
 
-  var j: IBase<String>
-    field = j
-    get
-    set
-
 }
+