[libcxx][ranges] implement `std::ranges::set_difference`

implement `std::ranges::set_difference`
reused classic std::set_difference
added unit tests

Differential Revision: https://reviews.llvm.org/D128983

NOKEYCHECK=True
GitOrigin-RevId: 1cdec6c96e852f4ebac61711a622535bcaf07542
diff --git a/include/module.modulemap.in b/include/module.modulemap.in
index b547b50..98bb00b 100644
--- a/include/module.modulemap.in
+++ b/include/module.modulemap.in
@@ -347,6 +347,7 @@
       module ranges_replace                  { private header "__algorithm/ranges_replace.h" }
       module ranges_replace_if               { private header "__algorithm/ranges_replace_if.h" }
       module ranges_reverse                  { private header "__algorithm/ranges_reverse.h" }
+      module ranges_set_difference           { private header "__algorithm/ranges_set_difference.h" }
       module ranges_sort                     { private header "__algorithm/ranges_sort.h" }
       module ranges_stable_sort              { private header "__algorithm/ranges_stable_sort.h" }
       module ranges_swap_ranges              { private header "__algorithm/ranges_swap_ranges.h" }