When doing a test-to-double conversion on a BLOB with an odd number of bytes

and assuming a UTF16 encoding, ignore the last byte.
Ticket [9eda2697f5cc1aba].

FossilOrigin-Name: 1c76f1d8ec0937a2d2e4ce75f98494c953e9621db31945d7e44f45d90d1c3892