[libcxx] Disable testing with system lib for 2 tests verifying debug mode.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@329023 91177308-0d34-0410-b5e6-96231b3b80d8

test/libcxx/thread/futures/futures.promise/set_exception.pass.cpp

@@ -14,6 +14,9 @@
 // MODULES_DEFINES: _LIBCPP_DEBUG_USE_EXCEPTIONS
 // MODULES_DEFINES: _LIBCPP_DEBUG=0
 
+// Can't test the system lib because this test enables debug mode
+// UNSUPPORTED: with_system_cxx_lib
+
 // <future>
 
 // class promise<R>

test/libcxx/thread/futures/futures.promise/set_exception_at_thread_exit.pass.cpp

@@ -14,6 +14,9 @@
 // MODULES_DEFINES: _LIBCPP_DEBUG_USE_EXCEPTIONS
 // MODULES_DEFINES: _LIBCPP_DEBUG=0
 
+// Can't test the system lib because this test enables debug mode
+// UNSUPPORTED: with_system_cxx_lib
+
 // <future>
 
 // class promise<R>