Modify an assert() within sqlite3PagerWalFramesize(), a function only ever used by zipvfs, to account for recent zipvfs changes.
Since numeric affinity is the most common case, check it first.  Interchange
the NONE and TEXT affinity codes for easier checking of no affinity.
Performance improvement for affinity transformations on comparison operators.
Merge the Mem.r value into the MemValue union as Mem.u.r.  Hence, a Mem can
now store an integer or a real but not both at the same time.  Strings are
still stored in a separate element Mem.z, for now.
Correct typos in comments.  No changes to code.
Add the Mem.szMalloc element to the Mem object and use it to keep track of
the size of the Mem.zMalloc allocation.
Add the sqlite3VdbeMemClearAndResize() interface to be used in place of
sqlite3VdbeMemGrow().
Make sure that the sorting-index pre-filter recognizes that a rowid reference
might be sortable.  This fixes a performance regression.
Add the sqlite3VdbeMemClearAndResize() function.  Fix a sorting-index
prefilter problem.