Cleanup non-standard tests as reported by STL@microsoft.com. NFC.

This patch addresses the following issues in the test suite:

1. Move "std::bad_array_length" test from std/ to libcxx/ test directory
   since the feature is not a part of the standard.

2. Rename "futures.tas" test directory to "futures.task" since that is the
   correct stable name.

3. Move tests for "packaged_task<T>::result_type" from std/ to libcxx/
   test directory since the typedef is a libc++ extension.


git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@271430 91177308-0d34-0410-b5e6-96231b3b80d8

test/libcxx/language.support/support.dynamic/alloc.errors/new.badlength/bad_array_length.pass.cpp

@@ -0,0 +1,28 @@
+//===----------------------------------------------------------------------===//
+//
+//                     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.
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++98, c++03, c++11
+// test bad_array_length
+
+#include <new>
+#include <type_traits>
+#include <cassert>
+
+int main()
+{
+    static_assert((std::is_base_of<std::bad_alloc, std::bad_array_length>::value),
+                  "std::is_base_of<std::bad_alloc, std::bad_array_length>::value");
+    static_assert(std::is_polymorphic<std::bad_array_length>::value,
+                 "std::is_polymorphic<std::bad_array_length>::value");
+    std::bad_array_length b;
+    std::bad_array_length b2 = b;
+    b2 = b;
+    const char* w = b2.what();
+    assert(w);
+}