Add a test to trigger GC.

Change-Id: I398465ae0129612d0f8742d129a4c82c796584a3
diff --git a/build/Android.common.mk b/build/Android.common.mk
index 5903eae..c200a0c 100644
--- a/build/Android.common.mk
+++ b/build/Android.common.mk
@@ -212,6 +212,7 @@
 	IntMath \
 	Interfaces \
 	Main \
+	MemUsage \
 	MyClass \
 	MyClassNatives \
 	Nested \