New J2K: Split old j2k and new j2k tests

nj2k/testData/newJ2k/detectProperties/DifferentProtectedFieldName.kt

@@ -0,0 +1,17 @@
+open class AAA {
+    var x = 42
+        protected set
+
+    fun foo(other: AAA) {
+        println(x)
+        println(other.x)
+        x = 10
+    }
+}
+
+internal class BBB : AAA() {
+    fun bar() {
+        println(x)
+        x = 10
+    }
+}