wasm: corrected the propagation of text/blob values via UDFs. DB.exec()'s sql may...

wasm: corrected the propagation of text/blob values via UDFs. DB.exec()'s sql may now be an array of strings which get concatenated together before passing it on to sqlite3_prepare_v2(). DB.exec()'s callback now applies to the first statement which has result columns instead of only the first statement. Fixed a precedence but which caused isInt32() to report false positives.

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