[gn build] Port 8f9cce0

Author: nico

llvm/utils/gn/secondary/libcxx/include/BUILD.gn

@@ -819,6 +819,7 @@ if (current_toolchain == default_toolchain) {
       "__type_traits/common_type.h",
       "__type_traits/conditional.h",
       "__type_traits/conjunction.h",
+      "__type_traits/container_traits.h",
       "__type_traits/copy_cv.h",
       "__type_traits/copy_cvref.h",
       "__type_traits/datasizeof.h",