[libcxx] [test] Add UNSUPPORTED: msvc in a couple verify.cpp tests

[mstorsjo]

Summary

Due to issues with the detection of the clang-verify feature, these
tests have been skipped in the Windows CI configuration so far.

[ldionne]

I'll admit I'd like it better if we could make MSVC mode match the regular Clang.

[mstorsjo]

In D103308#2786788, @ldionne wrote:

I'll admit I'd like it better if we could make MSVC mode match the regular Clang.

Yeah I can imagine that - although it's pretty much by design, where MSVC mode differs both in how errors are printed, and how the exact language gets evaluated.

libcxx/test/std/language.support/cmp/cmp.categories.pre/zero_type.verify.cpp

 // -*- C++ -*-
 //===----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: apple-clang-9, apple-clang-10, apple-clang-11, apple-clang-12.0.0
 
+// In MSVC mode, there's a slightly different number of errors printed for
+// each of these, so it doesn't add up to the exact expected count of 18.
+// UNSUPPORTED: msvc
+
 // <compare>
 
 // Ensure we reject all cases where an argument other than a literal 0 is used
 // for a comparison against a comparison category type.
 
 #include <compare>
 
 #define TEST_FAIL(v, op)                                                       \

libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/underlying_type.fail.cpp

 //===----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // type_traits
 
+// MSVC mode seems to use different rules regarding enum sizes, so E1
+// doesn't cause an error.
+// UNSUPPORTED: msvc
+
 // underlying_type
 // Mandates: enum must not be an incomplete enumeration type.
 
 #include <type_traits>
 #include <climits>
 
 #include "test_macros.h"