MDL-59561 database: Update to creating new indexes in mysql.

MDL-59561 database: Update to creating new indexes in mysql.

When updating the mysql system to utf8mb4 not all tables are
converted to the row format of compressed or dynamic. If a new
index is created there is a possibility that the table could be
using compact or redundant and then an error will be shown saying
that the index size is too large. This fix handles this exception
and converts the table over to compressed.