fixed a typo in StringBuilder

Change-Id: I640d45e056d90794648a73f7d5546c520d4a41df
diff --git a/user/super/com/google/gwt/emul/java/lang/StringBuilder.java b/user/super/com/google/gwt/emul/java/lang/StringBuilder.java
index 37eb242..eb87a52 100644
--- a/user/super/com/google/gwt/emul/java/lang/StringBuilder.java
+++ b/user/super/com/google/gwt/emul/java/lang/StringBuilder.java
@@ -231,7 +231,7 @@
     return this;
   }
 
-  public StringBuilder reserve() {
+  public StringBuilder reverse() {
     impl.reverse(data);
     return this;
   }