Fix Bug#56143 too many foreign keys causes output of show create table to become invalid

Just remove the check whether the file is "too big".
A similar code exists in ha_innobase::update_table_comment() but that
method does not seem to be used.

mysql-test/suite/innodb/t/innodb_bug56143.test

+#
+# Bug#56143 too many foreign keys causes output of show create table to become invalid
+# http://bugs.mysql.com/56143
+#
+
+-- source include/have_innodb.inc
+
+-- disable_query_log
+-- disable_result_log
+
+SET foreign_key_checks=0;
+DROP TABLE IF EXISTS bug56143;
+CREATE TABLE bug56143 (a INT, b INT, c INT, KEY(a), KEY(b), KEY(c)) ENGINE=INNODB;
+
+let $i = 550;
+while ($i)
+{
+	eval ALTER TABLE `bug56143` ADD CONSTRAINT `aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa$i` FOREIGN KEY (`b`) REFERENCES `bug56143`(`b`) ON UPDATE SET NULL;
+	dec $i;
+}
+
+-- enable_query_log
+-- enable_result_log
+
+SHOW CREATE TABLE bug56143;
+
+-- disable_query_log
+-- disable_result_log
+DROP TABLE bug56143;

storage/innobase/handler/ha_innodb.cc

@@ -6788,8 +6788,6 @@ ha_innobase::get_foreign_key_create_info(void)
 	flen = ftell(srv_dict_tmpfile);
 	if (flen < 0) {
 		flen = 0;
-	} else if (flen > 64000 - 1) {
-		flen = 64000 - 1;
 	}
 
 	/* allocate buffer for the string, and