Guard libc++ specific c.__invariants() tests in LIBCPP_ASSERT macros

llvm-svn: 267947
diff --git a/libcxx/test/std/strings/basic.string/string.cons/alloc.pass.cpp b/libcxx/test/std/strings/basic.string/string.cons/alloc.pass.cpp
index 1c4f204..a803d33 100644
--- a/libcxx/test/std/strings/basic.string/string.cons/alloc.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.cons/alloc.pass.cpp
@@ -29,7 +29,7 @@
 	static_assert((noexcept(S()) == noexcept(typename S::allocator_type())), "" );
 #endif
     S s;
-    assert(s.__invariants());
+    LIBCPP_ASSERT(s.__invariants());
     assert(s.data());
     assert(s.size() == 0);
     assert(s.capacity() >= s.size());
@@ -42,7 +42,7 @@
 	static_assert((noexcept(S(typename S::allocator_type())) == std::is_nothrow_copy_constructible<typename S::allocator_type>::value), "" );
 #endif
     S s(typename S::allocator_type(5));
-    assert(s.__invariants());
+    LIBCPP_ASSERT(s.__invariants());
     assert(s.data());
     assert(s.size() == 0);
     assert(s.capacity() >= s.size());
@@ -63,7 +63,7 @@
 	static_assert((noexcept(S()) == noexcept(typename S::allocator_type())), "" );
 #endif
     S s;
-    assert(s.__invariants());
+    LIBCPP_ASSERT(s.__invariants());
     assert(s.data());
     assert(s.size() == 0);
     assert(s.capacity() >= s.size());
@@ -76,7 +76,7 @@
 	static_assert((noexcept(S(typename S::allocator_type())) == std::is_nothrow_copy_constructible<typename S::allocator_type>::value), "" );
 #endif
     S s(typename S::allocator_type{});
-    assert(s.__invariants());
+    LIBCPP_ASSERT(s.__invariants());
     assert(s.data());
     assert(s.size() == 0);
     assert(s.capacity() >= s.size());