Fix linking error, undefined class static constants.

[Benoit]

I don't have write access to the repository. Can someone push this for me?

[Benoit]

rebased

[hoy]

In D121293#3370025, @Benoit wrote:

I don't have write access to the repository. Can someone push this for me?

Thanks for the fix! I can do the push.

llvm/lib/Transforms/Utils/SampleProfileInference.cpp

private:
   /// Source node of the flow.
   uint64_t Source;
   /// Target (sink) node of the flow.
   uint64_t Target;
   /// Augmenting edges.
   std::vector<std::vector<Edge *>> AugmentingEdges;
 };
 
+constexpr int64_t MinCostMaxFlow::AuxCostUnlikely;
+constexpr uint64_t MinCostMaxFlow::MinBaseDistance;
+
 /// A post-processing adjustment of control flow. It applies two steps by
 /// rerouting some flow and making it more realistic:
 ///
 /// - First, it removes all isolated components ("islands") with a positive flow
 ///   that are unreachable from the entry block. For every such component, we
 ///   find the shortest from the entry to an exit passing through the component,
 ///   and increase the flow by one unit along the path.
 ///