[libc++][test] Adds a missing include.

diff --git a/libcxx/test/std/time/time.syn/formatter_tests.h b/libcxx/test/std/time/time.syn/formatter_tests.h
index 115d6cc..42c176b 100644 (file)
--- a/libcxx/test/std/time/time.syn/formatter_tests.h
+++ b/libcxx/test/std/time/time.syn/formatter_tests.h
@@ -15,6 +15,7 @@
 
 #include <algorithm>
 #include <cassert>
+#include <iostream>
 #include <set>
 #include <string>
 #include <string_view>