MDEV-28062 Assertion `(length % 4) == 0' failed in my_lengthsp_utf32 on INSERT..SELECT

Adding an MTR test only.

This problem was earlier fixed by the patch for:
  MDEV-28078 Garbage on multiple equal ENUMs with tricky character sets

mysql-test/main/ctype_utf32_innodb.result

+#
+# Start of 10.3 tests
+#
+#
+# MDEV-28062 Assertion `(length % 4) == 0' failed in my_lengthsp_utf32 on INSERT..SELECT
+#
+SET sql_mode='';
+CREATE TABLE t1 (
+HOST CHAR DEFAULT '%',
+USER CHAR DEFAULT '%',
+ROLE CHAR DEFAULT '%',
+ENABLED ENUM ('a','a') DEFAULT 'a',
+HISTORY ENUM ('a','a') DEFAULT 'a'
+) COLLATE=utf32_general_ci ENGINE=InnoDB;
+Warnings:
+Note	1291	Column 'ENABLED' has duplicated value 'a' in ENUM
+Note	1291	Column 'HISTORY' has duplicated value 'a' in ENUM
+INSERT INTO t1 SELECT * FROM t1;
+DROP TABLE t1;
+CREATE TABLE t1 (
+HOST CHAR DEFAULT '%',
+USER CHAR DEFAULT '%',
+ROLE CHAR DEFAULT '%',
+ENABLED ENUM ('a','a') DEFAULT 'a',
+HISTORY ENUM ('a','a') DEFAULT 'a'
+) COLLATE=utf32_general_ci ENGINE=MyISAM;
+Warnings:
+Note	1291	Column 'ENABLED' has duplicated value 'a' in ENUM
+Note	1291	Column 'HISTORY' has duplicated value 'a' in ENUM
+INSERT INTO t1 SELECT * FROM t1;
+DROP TABLE t1;
+#
+# End of 10.3 tests
+#

mysql-test/main/ctype_utf32_innodb.test

+--source include/have_innodb.inc
+
+--echo #
+--echo # Start of 10.3 tests
+--echo #
+
+--echo #
+--echo # MDEV-28062 Assertion `(length % 4) == 0' failed in my_lengthsp_utf32 on INSERT..SELECT
+--echo #
+
+SET sql_mode='';
+
+CREATE TABLE t1 (
+  HOST CHAR DEFAULT '%',
+  USER CHAR DEFAULT '%',
+  ROLE CHAR DEFAULT '%',
+  ENABLED ENUM ('a','a') DEFAULT 'a',
+  HISTORY ENUM ('a','a') DEFAULT 'a'
+) COLLATE=utf32_general_ci ENGINE=InnoDB;
+INSERT INTO t1 SELECT * FROM t1;
+DROP TABLE t1;
+
+CREATE TABLE t1 (
+  HOST CHAR DEFAULT '%',
+  USER CHAR DEFAULT '%',
+  ROLE CHAR DEFAULT '%',
+  ENABLED ENUM ('a','a') DEFAULT 'a',
+  HISTORY ENUM ('a','a') DEFAULT 'a'
+) COLLATE=utf32_general_ci ENGINE=MyISAM;
+INSERT INTO t1 SELECT * FROM t1;
+DROP TABLE t1;
+
+--echo #
+--echo # End of 10.3 tests
+--echo #