Subsequent use of Statement::execute* methods may send incorrect value of input parameters

[asfernandes]

When parameter was set to null, all subsequent execution will use null instead of the passed values.

Test case:

const statement2 = await attachment.prepare(transaction, 'insert into t1 (n1) values (?)');
await statement2.execute(transaction, [1]);
await statement2.execute(transaction, [null]);
// Next executions will be incorrect!
await statement2.execute(transaction, [10]);
await statement2.execute(transaction, [100]);
await statement2.dispose();