fix missing dx in build server.

Change-Id: I18c49c5cc1efc97199cb076dc258c4b9b7a46e8a
diff --git a/test/089-many-methods/build b/test/089-many-methods/build
index 0bd90c2..7ede759 100644
--- a/test/089-many-methods/build
+++ b/test/089-many-methods/build
@@ -45,5 +45,5 @@
 
 mkdir classes
 ${JAVAC} -d classes `find src -name '*.java'`
-dx -JXmx1024m --dex --no-optimize classes
+${DX} -JXmx1024m --dex --no-optimize classes