How to clear the InnoDB redo log before starting mysqld for crash recovery
What you should be doing, is


kill mysqld process. Disable the MySQL service (or whatever it is called), if it runs as service.
upgrade to latest 10.2 (it is already on 10.2.24 as of today, you are using a very old version)
Enable the service and start again.


If it does not start again, take the mysqld process minidump while it is hanging, and submit a bug to JIRA https://jira.mariadb.org/browse/MDEV

This is definitely more helpful than trying to "recover" by deleting Innodb redo logs (this is one of the things you should not be doing).