dataflow to/from containers support

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

@@ -1,13 +1,13 @@
 class s {
     {
-      x(<flown11211>"xxx");
+      x(<flown1121111>"xxx");
     }
-    String x(String g) {
-        String d = <flown1>foo(<flown1121>g);
+    String x(String <flown112111>g) {
+        String d = <flown1>foo(<flown11211>g);
         return <caret>d;
     }
 
-    private String foo(String i) {
+    private String foo(String <flown1121>i) {
         return <flown11>i==null ? <flown111>null : <flown112>i;
     }
 }