[libc++] Move the definition of aligned allocation helpers outside of <new>

They are not needed in <new> -- in fact they are only needed in .cpp files.
Getting those out of the way makes the headers smaller and also makes it
easier to use the library on platforms where aligned allocation is not
available.

Differential Revision: https://reviews.llvm.org/D139231

NOKEYCHECK=True
GitOrigin-RevId: 36080434a8858c33f2af2382be748caed131385f
diff --git a/include/module.modulemap.in b/include/module.modulemap.in
index 1f1d67d..6bc64be 100644
--- a/include/module.modulemap.in
+++ b/include/module.modulemap.in
@@ -1061,6 +1061,7 @@
     module __memory {
       module addressof                       { private header "__memory/addressof.h" }
       module align                           { private header "__memory/align.h" }
+      module aligned_alloc                   { private header "__memory/aligned_alloc.h" }
       module allocate_at_least               { private header "__memory/allocate_at_least.h" }
       module allocation_guard                { private header "__memory/allocation_guard.h" }
       module allocator                       { private header "__memory/allocator.h" }