[libc++] Granularize <utility> includes

Reviewed By: ldionne, #libc

Spies: EricWF, libcxx-commits, arphaman

Differential Revision: https://reviews.llvm.org/D120466

NOKEYCHECK=True
GitOrigin-RevId: 52915d78f44bfc5add6cddc91d392fa343672897
diff --git a/include/fstream b/include/fstream
index 80bda63..2f1cd32 100644
--- a/include/fstream
+++ b/include/fstream
@@ -184,9 +184,12 @@
 #include <__availability>
 #include <__config>
 #include <__locale>
+#include <__utility/move.h>
+#include <__utility/swap.h>
 #include <__utility/unreachable.h>
 #include <cstdio>
 #include <cstdlib>
+#include <cstring>
 #include <istream>
 #include <ostream>
 #include <version>