Fix a resource leak: sqlite3_blob_reopen() was failing to invoke the

Fix a resource leak: sqlite3_blob_reopen() was failing to invoke the
xDel() distructor on a register when it sets that register to the new
rowid.  This was never a problem prior to the large-column cache of
[771fe35074b50b8d] as that destructor was always a no-op.
dbsqlfuzz cd96368deaece480fb94d42427dde053737a650e.

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