Remove obsolete comment from utf8.c

The call to save_re_context was removed by the previous commit.  The
commit before that stopped save_re_context from doing anything.

Commit db2c6cb stopped the errsv_save line from triggering
get-magic.

So this comment, added in dc0c6ab, no longer applies.

utf8.c

@@ -2370,14 +2370,6 @@ Perl__core_swash_init(pTHX_ const char* pkg, const char* name, SV *listsv, I32 m
 	    GvSV(PL_errgv) = NULL;
 	    /* It is assumed that callers of this routine are not passing in
 	     * any user derived data.  */
-	    /* XXX The following comment is out of date.  The
-	           save_re_context() call used to be right after
-		   SAVEHINTS() above, but no longer exists.  Does the
-		   errsv_save bit still apply?  */
-	    /* Need to do this after save_re_context() as it will set
-	     * PL_tainted to 1 while saving $1 etc (see the code after getrx:
-	     * in Perl_magic_get).  Even line to create errsv_save can turn on
-	     * PL_tainted.  */
 #ifndef NO_TAINT_SUPPORT
 	    SAVEBOOL(TAINT_get);
 	    TAINT_NOT;