test: Specify dependencies per-test

This reduces the dependency tree to enhance build parallelism.

Change-Id: Iee77dc9829ab404f987362918b4282ad6b8a4b28
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/test/fd/managed.cpp b/test/fd/managed.cpp
index 003c4e3..f365618 100644
--- a/test/fd/managed.cpp
+++ b/test/fd/managed.cpp
@@ -1,14 +1,4 @@
-#include <gtest/gtest.h>
 #include <stdplus/fd/managed.hpp>
-
-namespace stdplus
-{
-namespace fd
-{
-
-TEST(DupableFd, Noop)
+int main(int, char*[])
 {
 }
-
-} // namespace fd
-} // namespace stdplus