Fixes RichTextArea.Formatter.insertHTML for IE permutation

The regression was introduced in
I6ed65ede38b06ce42f51be9613a129a938f0bc048

Bug: issue 4265
Change-Id: I33c1a73c396e75cc91b51d762f523b618ae057ab
(cherry picked from commit 1a6e23cf69c3cd17b74ffa3aff77565f4bb63ad2)
diff --git a/user/src/com/google/gwt/user/client/ui/impl/RichTextAreaImplIE6.java b/user/src/com/google/gwt/user/client/ui/impl/RichTextAreaImplIE6.java
index 74fd238..faa9e10 100644
--- a/user/src/com/google/gwt/user/client/ui/impl/RichTextAreaImplIE6.java
+++ b/user/src/com/google/gwt/user/client/ui/impl/RichTextAreaImplIE6.java
@@ -78,7 +78,7 @@
       if (tr == null) {
         return;
       }
-      if (!@com.google.gwt.user.client.ui.impl.RichTextAreaImplIE6::isOrHasChild(*)(doc.body, tr.parentElement)) {
+      if (!@com.google.gwt.user.client.ui.impl.RichTextAreaImplIE6::isOrHasChild(*)(doc.body, tr.parentElement())) {
         return;
       }
       tr.pasteHTML(html);