[libcxx] [test] Include missing headers. (NFC)

libcxx/test/std/containers/sequences/array/at.pass.cpp
Need to include <stdexcept> for std::out_of_range.

libcxx/test/std/localization/locale.categories/category.time/*
Need to include <ios> for std::ios.
diff --git a/libcxx/test/std/containers/sequences/array/at.pass.cpp b/libcxx/test/std/containers/sequences/array/at.pass.cpp
index 0240d5a..0454643 100644
--- a/libcxx/test/std/containers/sequences/array/at.pass.cpp
+++ b/libcxx/test/std/containers/sequences/array/at.pass.cpp
@@ -16,6 +16,10 @@
 #include <array>
 #include <cassert>
 
+#ifndef TEST_HAS_NO_EXCEPTIONS
+#include <stdexcept>
+#endif
+
 #include "test_macros.h"
 
 // std::array is explicitly allowed to be initialized with A a = { init-list };.