Add tests for LWG#2299. While doing so, I noticed that the tests we have for the transparent comparators don't actually call them. Fix those tests, too. Now one of them is failing, due to a missing const in <map>. Add that (twice). Next step is to do the same for <unordered_map>

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@241091 91177308-0d34-0410-b5e6-96231b3b80d8

test/std/containers/associative/multimap/multimap.ops/count.pass.cpp

@@ -18,6 +18,7 @@
 
 #include "min_allocator.h"
 #include "private_constructor.hpp"
+#include "is_transparent.h"
 
 int main()
 {
@@ -122,6 +123,21 @@ int main()
     assert(r == 3);
     r = m.count(10);
     assert(r == 0);
+
+    r = m.count(C2Int(4));
+    assert(r == 0);
+    r = m.count(C2Int(5));
+    assert(r == 3);
+    r = m.count(C2Int(6));
+    assert(r == 0);
+    r = m.count(C2Int(7));
+    assert(r == 3);
+    r = m.count(C2Int(8));
+    assert(r == 0);
+    r = m.count(C2Int(9));
+    assert(r == 3);
+    r = m.count(C2Int(10));
+    assert(r == 0);
     }
 
     {