libc: Add free_sized() and free_aligned_sized() as per C23

Add C23 sized deallocation entry points as thin wrappers around free(3).
Implementations may ignore size and alignment hints, so behaviour stays
correct for existing allocations without validating caller metadata yet.

When jemalloc is updated to 5.3.1, rewire these to je_free_sized() and
je_free_aligned_sized() so deallocation can use the allocator's sized
deallocation (free_sized for fast paths and free_aligned_sized for
correct aligned hints.)

Please note this change satisfies the standard interface only. Both
functions should be delegated to jemalloc after the upgrade so callers
get the intended allocator behaviour; until then, hints are unused and
neither sized nor aligned-sized deallocation optimizations apply.

Signed-off-by:	Faraz Vahedi <[email protected]>
Reviewed by:	fuz
Pull Request:	https://github.com/freebsd/freebsd-src/pull/2201
MFC after:	1 month

include/stdlib.h

@@ -173,6 +173,8 @@ _Noreturn void
  */
 #if __ISO_C_VISIBLE >= 2023
 size_t	memalignment(const void *) __pure2;
+void	free_sized(void *, size_t) __noexcept;
+void	free_aligned_sized(void *, size_t, size_t) __noexcept;
 #endif /* __ISO_C_VISIBLE >= 2023 */
 
 /*