[MISched] Fix non-debug builds.

[fpetrogalli]

Summary

As reported in https://github.com/llvm/llvm-project/issues/63225, we
need to make sure we can use the &operator<< on instances of the
ResourceSegments class for builds that set NDEBUG.

[sylvestre.ledru]

thanks!

[fpetrogalli]

In D152817#4420903, @sylvestre.ledru wrote:

thanks!

De nada! :) Thank you for reporting the issue.

llvm/include/llvm/CodeGen/MachineScheduler.h

explicit ResourceSegments(std::list<IntervalTy> Intervals)
       : _Intervals(Intervals) {
     sortAndMerge();
   }
 
   friend bool operator==(const ResourceSegments &c1,
                          const ResourceSegments &c2) {
     return c1._Intervals == c2._Intervals;
   }
-#ifndef NDEBUG
   friend llvm::raw_ostream &operator<<(llvm::raw_ostream &os,
                                        const ResourceSegments &Segments) {
     os << "{ ";
     for (auto p : Segments._Intervals)
       os << "[" << p.first << ", " << p.second << "), ";
     os << "}\n";
     return os;
   }
-#endif
 };
 
 /// Each Scheduling boundary is associated with ready queues. It tracks the
 /// current cycle in the direction of movement, and maintains the state
 /// of "hazards" and other interlocks at the current cycle.
 class SchedBoundary {
 public:
   /// SUnit::NodeQueueId: 0 (none), 1 (top), 2 (bot), 3 (both)