inference: complete the inference even for recursive cycles (#56551)

We care more and more now that our inference graph exactly matches the
callgraph, even in cases like this where we can easily prove that the
inference graph is simpler than the full callgraph. However, given when
the optimizer runs, it expects this information to be available and
valid as soon as the cycles are completed.

Compiler/src/abstractinterpretation.jl

@@ -583,14 +583,6 @@ function abstract_call_method(interp::AbstractInterpreter,
             if infmi.specTypes::Type == sig::Type
                 # avoid widening when detecting self-recursion
                 # TODO: merge call cycle and return right away
-                if call_result_unused(si)
-                    add_remark!(interp, sv, RECURSION_UNUSED_MSG)
-                    # since we don't use the result (typically),
-                    # we have a self-cycle in the call-graph, but not in the inference graph (typically):
-                    # break this edge now (before we record it) by returning early
-                    # (non-typically, this means that we lose the ability to detect a guaranteed StackOverflow in some cases)
-                    return Future(MethodCallResult(Any, Any, Effects(), nothing, true, true))
-                end
                 topmost = nothing
                 edgecycle = true
                 break