Named the macro wrong in the test.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@318259 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/libcxx/diagnostics/nodiscard.pass.cpp b/test/libcxx/diagnostics/nodiscard.pass.cpp
index b001d67..7519799 100644
--- a/test/libcxx/diagnostics/nodiscard.pass.cpp
+++ b/test/libcxx/diagnostics/nodiscard.pass.cpp
@@ -13,7 +13,7 @@
 
 // UNSUPPORTED: c++98, c++03, c++11, c++14
 
-#define _LIBCPP_DISABLE_AFTER_CXX17_NODISCARD
+#define _LIBCPP_DISABLE_NODISCARD_AFTER_CXX17
 #include <__config>
 
 _LIBCPP_NODISCARD_AFTER_CXX17 int foo() { return 6; }