Java to Kotlin converter: declare private field with no writes as val

j2k/tests/testData/ast/comments/comments2.kt

@@ -11,7 +11,7 @@ class A() {
         /* body is empty */
     }
 
-    private /*it's private*/ var field = 0
+    private /*it's private*/ val field = 0
 
     public /*it's public*/ fun foo(): Char {
     }

j2k/tests/testData/ast/comments/fieldWithEndOfLineComment.kt

@@ -1,3 +1,3 @@
 class A() {
-    private var isOpen = true // ideally should be atomic boolean
+    private val isOpen = true // ideally should be atomic boolean
 }