Added PR number for failing win64 tests.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@177886 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/Tooling/clang-check-pwd.cpp b/test/Tooling/clang-check-pwd.cpp
index 048c9bf..463ed40 100644
--- a/test/Tooling/clang-check-pwd.cpp
+++ b/test/Tooling/clang-check-pwd.cpp
@@ -9,4 +9,5 @@
 invalid;
 
 // REQUIRES: shell
+// PR15590
 // XFAIL: win64