New J2K: Split old j2k and new j2k tests

nj2k/testData/newJ2k/nullability/FieldComparedWithNull3.kt

@@ -0,0 +1,11 @@
+internal class C {
+    var s: String? = ""
+}
+
+internal class D {
+    fun foo(c: C) {
+        if (null == c.s) {
+            println("null")
+        }
+    }
+}