Apply the changes to InnoDB and XtraDB that had been
inadvertently skipped in the merge
commit ae476868

That merge failure sabotaged part of MDEV-20127:
>Revert a problematic auto_increment_increment 'fix' from 2014.
>This involves replacing the MDEV-8827 fix and in 10.1,
>removing some WSREP instrumentation.

The code changes were re-merged manually by executing the following:

 # Get the parent of the problematic merge.
git checkout ae476868^
 # Perform the merge again.
git merge ae476868^2
 # Get the conflict resolution from that merge.
git checkout ae476868 .
 # Note: Any changes to these files were removed (empty diff)!
git diff HEAD storage/{innobase,xtradb}/handler/ha_innodb.cc
 # Apply the code changes:
git diff cf403934^2..MERGE_HEAD \
storage/{innobase,xtradb}/handler/ha_innodb.cc|
patch -p1