[turbofan] Deferred block spilling heuristic - first step.

src/compiler/instruction.h

Index: src/compiler/instruction.h
diff --git a/src/compiler/instruction.h b/src/compiler/instruction.h
index a87ef7dc9c469f865919aeef34a79fbaacb5e033..5096b3b5fb147220f4c527fc876285a9eac1dc5a 100644
--- a/src/compiler/instruction.h
+++ b/src/compiler/instruction.h
@@ -782,6 +782,10 @@ class RpoNumber final {
     return this->index_ == other.index_;
   }
 
+  bool operator<(RpoNumber other) const { return index_ < other.index_; }
+
+  bool operator>(RpoNumber other) const { return index_ > other.index_; }
+
  private:
   explicit RpoNumber(int32_t index) : index_(index) {}
   int32_t index_;