fdtrack: add wrapper for eventfd.

Bug: https://issuetracker.google.com/154450436
Test: bionic-unit-tests
Change-Id: I59013f0c4da0debbcc50269c64ae9db0cdc4eaa0
diff --git a/tests/fdtrack_test.cpp b/tests/fdtrack_test.cpp
index 4b289e9..e58ff79 100644
--- a/tests/fdtrack_test.cpp
+++ b/tests/fdtrack_test.cpp
@@ -23,6 +23,7 @@
 #include <netinet/in.h>
 #include <stdlib.h>
 #include <sys/epoll.h>
+#include <sys/eventfd.h>
 #include <sys/types.h>
 #include <unistd.h>
 
@@ -205,6 +206,8 @@
 FDTRACK_TEST(epoll_create, epoll_create(1));
 FDTRACK_TEST(epoll_create1, epoll_create1(0));
 
+FDTRACK_TEST(eventfd, eventfd(0, 0));
+
 #if 0
 // Why is this generating an extra socket/close event?
 FDTRACK_TEST(accept, ({