The test innodb.log_file_size_checkpoint was originally added to
MySQL 5.7 by me in a bug fix, to fix the interaction of WL#6494
(redo log resizing, introduced in MySQL 5.6) and WL#7142
(data file discovery based on MLOG_FILE_NAME records,
introduced in MySQL 5.7):

commit 70f9ef4e1220827132b50275ca7272f2bcca1864
Author: Marko Mäkelä <marko.makela@oracle.com>
Date:   Wed May 21 13:31:29 2014 +0300

    Bug#18755095 REDO LOG SIZE CHANGE AFTER CRASH RESULTS IN CHECKPOINT AGE
    ERROR MESSAGE

    This is a regression from fixing
    Bug#18730524 REPEATED KILL+RESTART FAILS DUE TO MISSING MLOG_FILE_NAME
    RECORD

    innobase_start_or_create_for_mysql(): Invoke fil_names_clear() before
    creating the "checkpoint" when changing redo log files.

    Approved by Jimmy Yang on IM.

The relevant part of the test is that fil_names_clear() is invoked to
emit an MLOG_CHECKPOINT record before the redo log files are deleted.
In case the server is killed before ib_logfile0 has been deleted,
the old (not-yet-resized) redo log will be treated as valid. We do not
need to create a large number of tables for that.