Fix friends_runme.*

Most of these test D_d twice when they really should be testing
D_d once and D_i once (the variable name is `di` and the values
assigned are integers).

This was wrong in the initial version for Python in
708021a809 and it looks like subsequent
additions for other languages have just copied that mistake.

Examples/test-suite/java/friends_runme.java

@@ -32,7 +32,7 @@ public class friends_runme {
     if (friends.mix(a,b) != 5)
       throw new RuntimeException("failed");
 
-    D_d di = new D_d(2);
+    D_i di = new D_i(2);
     D_d dd = new D_d(3.3);
 
     // incredible template overloading working just fine