test: read TAP status before exit

test/hash/siphash.cpp

@@ -32,4 +32,6 @@ main ()
         util::hash::siphash<2,4> h (t.key);
         tap.expect_eq (h (t.data), t.digest, "%s", t.message);
     }
+
+    return tap.status ();
 }

test/job/spinlock.cpp

@@ -62,4 +62,6 @@ main ()
 
         tap.expect (true, "n-way fight, %! contestants", std::thread::hardware_concurrency ());
     }
+
+    return tap.status ();
 }

test/job/ticketlock.cpp

@@ -90,4 +90,6 @@ main ()
         std::cout << rel << '\n';
         tap.expect_lt (rel, 0.1f, "reasonably fair under contention");
     }
+
+    return tap.status ();
 }