Test test_components.ml is bound to fail sometimes

[OlivierNicole]

When running dune runtest -p ocamlgraph on version 2.0.0 of this repo (actually using ocamlgraph to test some changes that I made in the compiler), I noticed that tests/test_components.ml had failed.

Looking at it, I can see why: it creates a random undirected graph with 10 vertices and 3 edges, computes its strongly connected components, prints it, and compares the output with some reference file.

I argue that it is strange to make it an “expect” test since it is bound to fail sometimes.