The test that was added in commit e05650e6
would break a subsequent run of a test encryption.innodb-bad-key-change
because some pages in the system tablespace would be encrypted with
a different key.

The failure was repeatable with the following invocation:

./mtr --no-reorder \
encryption.create_or_replace,cbc \
encryption.innodb-bad-key-change,cbc

Because the crash was unrelated to the code changes that we reverted
in commit eb38b1f7
we can safely re-apply those fixes.