Fix the MicrosoftExtensions.c target

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@212393 91177308-0d34-0410-b5e6-96231b3b80d8

test/Parser/MicrosoftExtensions.c

+// REQUIRES: x86-registered-target
 // RUN: %clang_cc1 -triple i386-mingw32 -fsyntax-only -verify -fms-extensions  -Wno-missing-declarations -x objective-c++ %s
 __stdcall int func0();
 int __stdcall func();