#1137 Revert 1137-enable-optimized-s7-blocks

Apparently, reverting the merge itself has bad side effects if we ever find we do want these changes, as described in https://github.com/git/git/blob/master/Documentation/howto/revert-a-faulty-merge.txt so I opted for reverting each commit instead.

This branch reverts the changes brought in by merge ed882557808de5b88b2778717fbdf112f642eb05 which merged branch 1137-enable-optimized-s7-blocks as a backward sequence of individual reverted commits from the original branch. The precise commits are in the log messages.

1137-enable-optimized-s7-blocks:

Revert of that:

Closes #1137 (closed)