Enable assertions in LayoutLib create

Change-Id: Ia74285ae50f5caf118aab9eca4123f8aa71f27b4
diff --git a/tools/layoutlib/Android.mk b/tools/layoutlib/Android.mk
index 1942831..ead3b13 100644
--- a/tools/layoutlib/Android.mk
+++ b/tools/layoutlib/Android.mk
@@ -61,7 +61,7 @@
 	$(hide) mkdir -p $(dir $@)
 	$(hide) rm -f $@
 	$(hide) ls -l $(built_framework_classes)
-	$(hide) java -jar $(built_layoutlib_create_jar) \
+	$(hide) java -ea -jar $(built_layoutlib_create_jar) \
 	             $@ \
 	             $(built_core_classes) \
 	             $(built_framework_classes) \