Remove undefined behavior from tests; specifically, ensure that the value type of the allocators match the value type of the containers

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@254030 91177308-0d34-0410-b5e6-96231b3b80d8

test/std/containers/associative/map/map.access/index_rv_key.pass.cpp

@@ -38,7 +38,7 @@ int main()
     assert(m.size() == 2);
     }
     {
-    typedef std::pair<MoveOnly, double> V;
+    typedef std::pair<const MoveOnly, double> V;
     std::map<MoveOnly, double, std::less<MoveOnly>, min_allocator<V>> m;
     assert(m.size() == 0);
     assert(m[1] == 0.0);