[libc++] Fix tests for the runtime assertions in <barrier>

[diamante0018]

Summary

As @ldionne pointed out to me in a newer revision, there is a //REQUIRE comment in both files edited by this patch that prevents the test to run on some platforms where it should actually run.

[ldionne]

LGTM. Please rebase on top of main to ensure you get a green CI run. In the current state of things you'll see some red, so I'll cancel your CI job.

[diamante0018]

rebase

[diamante0018]

Since the CI turned green here are my details.

Edoardo Sanguineti<[e-mail]>

Thanks

libcxx/test/libcxx/thread/thread.barrier/assert.arrive.pass.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: no-threads
 // UNSUPPORTED: c++03, c++11, c++14, c++17
+// UNSUPPORTED: !libcpp-has-hardened-mode && !libcpp-has-debug-mode
 
-// REQUIRES: availability-synchronization_library-missing
-// XFAIL: target={{.+}}-apple-macosx10.{{13|15}}
+// XFAIL: availability-verbose_abort-missing
 
 // REQUIRES: has-unix-headers
-// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_ENABLE_ASSERTIONS=1
 
 // <barrier>
 
 // class barrier;
 
 // void arrive(ptrdiff_t __update = 1);
 
 // Make sure that calling arrive with a negative value or with a value greater than 'expected' triggers an assertion

libcxx/test/libcxx/thread/thread.barrier/assert.ctor.pass.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: no-threads
 // UNSUPPORTED: c++03, c++11, c++14, c++17
+// UNSUPPORTED: !libcpp-has-hardened-mode && !libcpp-has-debug-mode
 
-// REQUIRES: availability-synchronization_library-missing
-// XFAIL: target={{.+}}-apple-macosx10.{{13|15}}
+// XFAIL: availability-verbose_abort-missing
 
 // REQUIRES: has-unix-headers
-// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_ENABLE_ASSERTIONS=1
 
 // <barrier>
 
 // class barrier;
 
 // barrier(ptrdiff_t __count, _CompletionF __completion = _CompletionF());
 
 // Make sure that constructing barrier with a negative value triggers an assertion