Closes#1948
This PR also adds pretty basic support for [row values in UPDATE stateme
nts](https://sqlite.org/rowvalue.html#row_values_in_update_statements),
but it only accepts expressions like:
```sql
UPDATE t SET (a, b) = (2 + 2, 'joe');
```
While SQLite accepts whole new statements, like:
```sql
UPDATE tab3
SET (a,b,c) = (SELECT x,y,z
FROM tab4
WHERE tab4.w=tab3.d)
WHERE tab3.e BETWEEN 55 AND 66;
```
I noticed we don't explicitly have the concept of row values, maybe
doing some plumbing in that matter could solve it?
If there is a way to implement that with our current infrastructure
(a.k.a skill issue from my side) please comment here.
Closes#2355