Add a test that getaddrinfo works when hints are NULL.

Bug: 1827911
Change-Id: I9e1b774c44c10a8c5391bcf3baf1607f50eaf214
diff --git a/tests/Android.mk b/tests/Android.mk
index 8138cff..eb97e6c 100644
--- a/tests/Android.mk
+++ b/tests/Android.mk
@@ -63,6 +63,7 @@
     getcwd_test.cpp \
     libgen_test.cpp \
     math_test.cpp \
+    netdb_test.cpp \
     pthread_test.cpp \
     regex_test.cpp \
     signal_test.cpp \