test: change argument

This failed on AArch64 due to the type mismatch using int instead of
__builtin_va_list.

llvm-svn: 250112

clang/test/CodeGen/Inputs/stdio.h

@@ -5,5 +5,5 @@ extern int vprintf(const char *format, __builtin_va_list arg);
 extern __inline __attribute__((gnu_inline,always_inline)) int
 vprintf(const char *x, __builtin_va_list y)
 {
-  return vfprintf (0, 0, 0);
+  return vfprintf (0, 0, y);
 }