asan: Mark printf-4.c as unsupported on Windows.

[pcc]

Summary

Although sprintf is not intercepted on Windows, this test can pass
if sprintf calls memmove, which is intercepted, so we can't XFAIL it.

[rnk]

lgtm Thanks for the investigation. I RDPd to the bot and then got distracted before debugging it.

compiler-rt/test/asan/TestCases/printf-4.c

 // RUN: %clang_asan -O2 %s -o %t
 // RUN: %env_asan_opts=check_printf=1 not %run %t 2>&1 | FileCheck --check-prefix=CHECK-ON %s
 // RUN: not %run %t 2>&1 | FileCheck --check-prefix=CHECK-ON %s
 
-// FIXME: sprintf is not intercepted on Windows yet.
-// XFAIL: win32
+// FIXME: sprintf is not intercepted on Windows yet. But this test can
+// pass if sprintf calls memmove, which is intercepted, so we can't XFAIL it.
+// UNSUPPORTED: win32
 
 #include <stdio.h>
 int main() {
   volatile char c = '0';
   volatile int x = 12;
   volatile float f = 1.239;
   volatile char s[] = "34";
   volatile char buf[2];