Add tests for Android-specific stubs

Also fix problem with multi-user IDs that the home directory was
returned as "/data" instead of "/" unlike all the other uids.

Change-Id: I914d22052e5a86552989f8969b85aadbc748c65d
diff --git a/tests/Android.mk b/tests/Android.mk
index 6d30ebb..be47585 100644
--- a/tests/Android.mk
+++ b/tests/Android.mk
@@ -23,6 +23,7 @@
     pthread_test.cpp \
     regex_test.cpp \
     string_test.cpp \
+    stubs_test.cpp \
 
 test_dynamic_ldflags = -Wl,--export-dynamic -Wl,-u,DlSymTestFunction
 test_dynamic_src_files = \