Fix crash on Super.getattr for previously uninferable attributes

[DanielNoord]

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Description

Will close when merged: #pylint-dev/pylint#5679

Pretty difficult to replicate this, but whenever the result of the inference was Uninferable we did not add that to the cache. Instead we added [] to the cache as this is how results is initialised. On a next try of inference of that node we see that the node is in the cache and yield from the empty list instead of yielding Uninferable. This seems only relevant whenever we get more than 100+ inference tries for a single node, which I think was happening with the sqlalchemy node.

Type of Changes

	Type
✓	🐛 Bug fix

Related Issue

[Pierre-Sassoulas]

Looks very good already !

[Pierre-Sassoulas]

👍

[drothlis]

This also fixes pylint no-member false positives: no-member doesn't warn if the owner is Uninferable, but because of this bug the Uninferable value was missing from infer().