Reuse skip_trailing_space() in my_hash_sort_utf8mbX

diff --git a/strings/ctype-utf8.c b/strings/ctype-utf8.c

index b8e71b1f7a9..7434f968383 100644

--- a/strings/ctype-utf8.c

+++ b/strings/ctype-utf8.c

@@ -4992,13 +4992,11 @@ static void my_hash_sort_utf8mb3_nopad(CHARSET_INFO *cs, const uchar *s, size_t

 static void my_hash_sort_utf8mb3(CHARSET_INFO *cs, const uchar *s, size_t slen,

                                  ulong *nr1, ulong *nr2)

 {

-  const uchar *e= s+slen;

   /*

     Remove end space. We have to do this to be able to compare

     'A ' and 'A' as identical

   */

-  while (e > s && e[-1] == ' ')

-    e--;

+  const uchar *e= skip_trailing_space(s, slen);

   my_hash_sort_utf8mb3_nopad(cs, s, e - s, nr1, nr2);

 }

@@ -7436,13 +7434,11 @@ static void

 my_hash_sort_utf8mb4(CHARSET_INFO *cs, const uchar *s, size_t slen,

                      ulong *nr1, ulong *nr2)

 {

-  const uchar *e= s + slen;

   /*

     Remove end space. We do this to be able to compare

     'A ' and 'A' as identical

   */

-  while (e > s && e[-1] == ' ')

-    e--;

+  const uchar *e= skip_trailing_space(s, slen);

   my_hash_sort_utf8mb4_nopad(cs, s, e - s, nr1, nr2);

 }