@deprecate the rest method that takes a string, and add another that …

…takes a Node that is consistent with how the AST is built.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=171883458

src/com/google/javascript/rhino/IR.java

@@ -595,8 +595,14 @@ public static Node stringKey(String s, Node value) {
     return stringKey;
   }
 
+  @Deprecated
   public static Node rest(String name) {
-    return new Node(Token.REST, name(name));
+    return rest(name(name));
+  }
+
+  public static Node rest(Node target) {
+    checkState(target.isValidAssignmentTarget(), target);
+    return new Node(Token.REST, target);
   }
 
   public static Node spread(Node expr) {