Protect tests that expect an exception for an unknown std::random_device

[rogfer01]

Summary

Skip these tests under libcpp-no-exceptions.

[mclow.lists]

LGTM

libcxx/trunk/test/std/numerics/rand/rand.device/ctor.pass.cpp

 //===----------------------------------------------------------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is dual licensed under the MIT and the University of Illinois Open
 // Source Licenses. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 
-// XFAIL: libcpp-no-exceptions
 // <random>
 
 // class random_device;
 
 // explicit random_device(const string& token = implementation-defined);
 
 // For the following ctors, the standard states: "The semantics and default
 // value of the token parameter are implementation-defined". Implementations

 #endif
 }
 
 void check_random_device_valid(const std::string &token) {
   std::random_device r(token);
 }
 
 void check_random_device_invalid(const std::string &token) {
+#ifndef TEST_HAS_NO_EXCEPTIONS
   try {
     std::random_device r(token);
     LIBCPP_ASSERT(false);
   } catch (const std::system_error&) {
   }
+#endif
 }
 
 
 int main() {
   {
     std::random_device r;
   }
   {

libcxx/trunk/test/std/numerics/rand/rand.device/eval.pass.cpp

 //===----------------------------------------------------------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is dual licensed under the MIT and the University of Illinois Open
 // Source Licenses. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 
-// XFAIL: libcpp-no-exceptions
 // <random>
 
 // class random_device;
 
 // result_type operator()();
 
 #include <random>
 #include <cassert>
 
 #include "test_macros.h"
 
 int main()
 {
     {
         std::random_device r;
         std::random_device::result_type e = r();
     }
 
+#ifndef TEST_HAS_NO_EXCEPTIONS
     try
     {
         std::random_device r("/dev/null");
         r();
         LIBCPP_ASSERT(false);
     }
     catch (const std::system_error&)
     {
     }
+#endif
 }