dataflow to/from containers support

java/java-tests/testData/codeInsight/slice/backward/GroupByLeavesWithLists.java

@@ -0,0 +1,23 @@
+import java.util.ArrayList;
+import java.util.List;
+
+public class ListTack {
+
+    void f(String s) {
+        String <caret>p = s;
+    }
+    void g(List<String> list) {
+        list.add(1, "uuu");
+
+        f(list.get(0));
+        f(list.remove(0));
+    }
+    void h() {
+        List<String> g = new ArrayList<String>();
+        g.add("zzz");
+        List<String> list = new ArrayList<String>();
+        list.add("xxx");
+        g(list);
+    }
+
+}