Reduce size of functional tests for Stack

[fviernau]

The expected results are so large that using IntelliJ for editing and meld for comparing diffs is not feasible.
Also reviewing a diff in GitHub UI will probably be impossible.

Goal: Reduce the size of the dependency trees of the test project(s), to address above issue plus maybe also the execution time.

[sschuberth]

Couldn't that be solved by finally migrating the Stack implementation to the dependency graph (see #3825) and comparing the more compact representations?

[fviernau]

Couldn't that be solved by finally migrating the Stack implementation to the dependency graph (see #3825) and comparing the more compact representations?

IIUC we never compare the dependency graph representation as that would be too cryptic (e.g. array indices and so forth), but use the legacy representation for human readability in expected results. So, I believe that wouldn't be a feasible solution.