Add Character.isBmpCodePoint.

Change-Id: Iaf54bf5c5036f3d5b5a870d15938e4fdc01ee8ea
diff --git a/user/super/com/google/gwt/emul/java/lang/Character.java b/user/super/com/google/gwt/emul/java/lang/Character.java
index 36077fa..5ebeccc 100644
--- a/user/super/com/google/gwt/emul/java/lang/Character.java
+++ b/user/super/com/google/gwt/emul/java/lang/Character.java
@@ -226,6 +226,10 @@
     return c;
   }
 
+  public static boolean isBmpCodePoint(int codePoint) {
+    return codePoint >= MIN_VALUE && codePoint <= MAX_VALUE;
+  }
+
   /*
    * TODO: correct Unicode handling.
    */