Fixes: (1) In the ->> function, instead of setting a subtype and clearing it,

Fixes:  (1) In the ->> function, instead of setting a subtype and clearing it,
do not set it in the first place, as doing the set would trigger an error
under SQLITE_STRICT_SUBTYPE.  (2) Allow the SQLITE_STRICT_SUBTYPE through
the property filter on sqlite3_create_function().

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