gh-36493: improve method `cycle_basis` for graphs with multiple edges
We use the notion of nearest common ancestor in a tree to find cycles
more efficiently than using DFS.
This is used only when the graph allows multiple edges, since otherwise
we use the method of networkx. Therefore, the failing doctests reported
in #36486 when using networkx 3.2 are independent from the changes done
here.
An additional optimization would be to determine the minimum spanning
tree, the ranks and the parents at the same time. We don't do it here.
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URL: https://github.com/sagemath/sage/pull/36493
Reported by: David Coudert
Reviewer(s): Kwankyu Lee
