[compiler-rt/asan] Disable irrelevant unittest on win64

Summary:
This test is allocating a 1gig chunk to make shadow allocation failed,
but on 64-bits architecture the test is working.

Reviewers: rnk

Subscribers: kubabrecka, llvm-commits, wang0109, chrisha

Differential Revision: https://reviews.llvm.org/D22553

llvm-svn: 276122

compiler-rt/test/asan/TestCases/Windows/shadow_mapping_failure.cc

@@ -1,5 +1,6 @@
 // RUN: %clang_cl_asan -O0 %s -Fe%t
 // RUN: not %run %t 2>&1 | FileCheck %s
+// REQUIRES: asan-32-bits
 
 #include <stdio.h>