Fix wrong answer in serial aggregation over inline varchar column by...

...calling allocateObjectFromInlinedValue in MaxAgg and MinAgg.
Heads up: the new version of HSQL rejects ORDER BY on a table aggregation like this. And our tests do this all the time. I was initially leaning towards acceding to the new strictness, possibly allowing it to break existing user code, but maybe it's better -- friendlier, possibly more standard -- to change the new HSQL code and/or ours to just quietly ignore the ORDER BY in these cases. I'm not sure.

In any case, I wouldn't suggest the ORDER BY here -- I don't think it is guaranteed to have any particular effect.