[libc++] Move __memory/utilities.h to __memory/allocation_guard.h

This matches the granularity of other headers that were split off of <__memory>.

GitOrigin-RevId: e98060fa72ccb3c43d359dc5842f7d102dcf4378
diff --git a/include/memory b/include/memory
index b3c1a86..ae3c2ce 100644
--- a/include/memory
+++ b/include/memory
@@ -679,6 +679,7 @@
 #include <stdexcept>
 #include <cstring>
 #include <__memory/addressof.h>
+#include <__memory/allocation_guard.h>
 #include <__memory/allocator.h>
 #include <__memory/allocator_traits.h>
 #include <__memory/auto_ptr.h>
@@ -691,7 +692,6 @@
 #include <__memory/temporary_buffer.h>
 #include <__memory/uninitialized_algorithms.h>
 #include <__memory/unique_ptr.h>
-#include <__memory/utilities.h>
 #include <version>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)