New J2K: convert all custom post-processing to applicability based ones

nj2k/testData/newJ2k/assignmentExpression/nullability-settings.kt

@@ -1,7 +1,7 @@
 internal class Foo {
     fun foo(o: HashSet<*>) {
         val o2: HashSet<*> = o
-        var foo: Int = 0
+        var foo = 0
         foo = o2.size
     }
 }