ASTTests/DeclTest.cpp: Tweak on msvc target to add "-fno-ms-extensions".

MS extensions don't prefer imaginary suffix even with -std=c++11.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@183301 91177308-0d34-0410-b5e6-96231b3b80d8

unittests/AST/DeclTest.cpp

@@ -27,6 +27,7 @@ TEST(Decl, CleansUpAPValues) {
   // allocate memory. This test only fails if run under valgrind with full leak
   // checking enabled.
   std::vector<std::string> Args(1, "-std=c++11");
+  Args.push_back("-fno-ms-extensions");
   ASSERT_TRUE(runToolOnCodeWithArgs(
       Factory->create(),
       "struct X { int a; }; constexpr X x = { 42 };"