fix(UPDATE): only perform subselect matching if necessary

[patricebender]

the issue was that while calculating the UPDATE.elements, we accidentially assumed that the calculated element would lead to a join, hence we did our subselect matching. This logic is not necessary for non SELECT queries --> there we need joins if we do a SELECT * from <entity with calculated element /w path expression>

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fix(UPDATE): no assocs in list which matches subquery results

[danjoa]

I tested it and it works in general 👍, but found one glitch, though:

await UPDATE `Orders.Items` .set `quantity = 0`
await UPDATE `Orders.Items` .set `quantity = 11` .where ({ up__ID: 'Order1' })
await UPDATE `Orders.Items` .set `quantity = 12` .where ({ up_: 'Order1' }) // auto-coercing to up__ID?
await UPDATE `Orders.Items` .set `quantity = 13` .where ({ up_: {ID:'Order1'} }) // FAILS

TODO: → the last one should work as well, shouldn't it?

await UPDATE `Orders['Order1']:Items` .set `quantity = 21`
await UPDATE `Orders[ID='Order1']:Items` .set `quantity = 22`
await UPDATE `Orders[discount=0.2]:Items` .set `quantity = 23`
await UPDATE `Orders.Items` .set `quantity = 31` .where `1=1`
await UPDATE `Orders:Items` .set `quantity = 32`

→ all work as expected 👍

[danjoa]

P.S. We might want to cove all the cases above also in our tests