Object: Add XFAILed test case for r239560.

We ought to also emit unmangled references to dllimported functions,
but no existing linker needs this.

llvm-svn: 240562

llvm/test/Object/dllimport-globalref.ll

@@ -0,0 +1,14 @@
+; RUN: llvm-as %s -o - | llvm-nm - | FileCheck %s
+
+; We should technically emit an unmangled reference to f here,
+; but no existing linker needs this.
+
+; XFAIL: *
+
+target datalayout = "e-m:w-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-pc-windows-msvc"
+
+; CHECK: U f
+
+declare dllimport void @f()
+@fp = constant void ()* @f