KT-19565: J2K: Determine mutability using iterator

#KT-19565 fixed

j2k/testData/fileOrElement/mutableCollections/Iterator2.java

@@ -0,0 +1,14 @@
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.List;
+
+public class TestMutableCollection {
+    public final List<String> list = new ArrayList<>();
+
+    public void test() {
+        for (Iterator<String> it = list.iterator(); it.hasNext(); ) {
+            String s = it.next();
+            if (s.equals("")) it.remove();
+        }
+    }
+}