Enhance the DELETE logic so that it can make use of WHERE_ONEPASS_DESIRED
for rowid tables.
The one-pass optimization is now working for DELETE on WITHOUT ROWID tables.
Combine the rowid and WITHOUT ROWID paths for DELETE into a single path.
Fix an OOM-recovery problem in the DELETE code generator.
Fix a couple of minor problems with the new delete logic.
Make sure one-pass DELETE for WITHOUT ROWID tables correctly positions the
PRIMARY KEY cursor.  Make the same fix for UPDATE.
Enable the ONEPASS optimization for DELETE, for both rowid and WITHOUT
ROWID tables.
Fix a problem with the shell tool EXPLAIN indentation code and VDBE sub-programs.