test: fix a phase divergence test case to actually not contains conflict The previous test case had a conflict, but that conflict is currently not raise by phase divergence resolution. This is an independent bug to solve.

tests: use current instability names everywhere

test: apply unstability resolution to `test-unstability-resolution-result.t` The test cases in this file probably deserved to be dispatched in other more thematic test file.

test: rename and clarify content of test-unstable-content-divergent.t The troubles → instabilities renaming was not applied here.