[libcxx] Rework sized delete.

Summary:
This patch does 2 main things:
1. Enable sized delete if the feature test macro `__cpp_sized_deallocation` is enabled.
2. Rework and cleanup all of the sized delete tests.

Test Plan:
The sized delete replacement tests are now split into 4 files:
1. sized_delete11.pass.cpp: Ensure overriding sized delete in C++11 has no effect.
2. sized_delete14.pass.cpp: Test overriding sized delete in C++14 and ensure it is called. This test fails on clang and GCC < 5.1. 
3. size_delete_calls_unsized_delete_.pass.cpp: Test that the default sized delete calls unsized delete.
4. sized_delete_fsizeddeallocation.pass.cpp: Test overriding sized delete when -fsized-deallocation is passed. This test should pass on clang and GCC >= 5.1

I have also removed a lot of cruft from the old tests. They no longer replace the new handler and tests that it is called for bad allocations.

Reviewers: mclow.lists

Reviewed By: mclow.lists

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D9831

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@237662 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/new b/include/new
index 11f8fe6..d2b2ae6 100644
--- a/include/new
+++ b/include/new
@@ -136,7 +136,8 @@
 _LIBCPP_NEW_DELETE_VIS void* operator new(std::size_t __sz, const std::nothrow_t&) _NOEXCEPT _NOALIAS;
 _LIBCPP_NEW_DELETE_VIS void  operator delete(void* __p) _NOEXCEPT;
 _LIBCPP_NEW_DELETE_VIS void  operator delete(void* __p, const std::nothrow_t&) _NOEXCEPT;
-#if defined(_LIBCPP_BUILDING_NEW) || _LIBCPP_STD_VER >= 14
+#if defined(_LIBCPP_BUILDING_NEW) || _LIBCPP_STD_VER >= 14 || \
+    (defined(__cpp_sized_deallocation) && __cpp_sized_deallocation >= 201309)
 _LIBCPP_NEW_DELETE_VIS void  operator delete(void* __p, std::size_t __sz) _NOEXCEPT;
 #endif
 
@@ -148,7 +149,8 @@
 _LIBCPP_NEW_DELETE_VIS void* operator new[](std::size_t __sz, const std::nothrow_t&) _NOEXCEPT _NOALIAS;
 _LIBCPP_NEW_DELETE_VIS void  operator delete[](void* __p) _NOEXCEPT;
 _LIBCPP_NEW_DELETE_VIS void  operator delete[](void* __p, const std::nothrow_t&) _NOEXCEPT;
-#if defined(_LIBCPP_BUILDING_NEW) || _LIBCPP_STD_VER >= 14
+#if defined(_LIBCPP_BUILDING_NEW) || _LIBCPP_STD_VER >= 14 || \
+    (defined(__cpp_sized_deallocation) && __cpp_sized_deallocation >= 201309)
 _LIBCPP_NEW_DELETE_VIS void  operator delete[](void* __p, std::size_t __sz) _NOEXCEPT;
 #endif