JIT: Replace fgMoveHotJumps with 3-opt utility (dotnet#112016)

Part of dotnet#107749. Based on the plans outlined in dotnet#111989 (comment), we want to remove phases that prematurely tweak the initial layout fed into 3-opt; fgMoveHotJumps is one such phase. However, initial attempts to remove it incurred large size increases on x86/x64, suggesting there was some utility in moving blocks closer to their hottest successors to keep the layout compact. To avoid derailing my consolidation plan, I've decided to refactor fgMoveHotJumps into a utility for 3-opt to use. For now, we will continue to use this pass to try to keep the layout compact. In the future, this functionality may be useful for churning the initial layout into 3-opt to discover new local-optimal layouts.

Author: amanasifkhalid

src/coreclr/jit/compiler.h

@@ -6371,24 +6371,23 @@ class Compiler
 #endif // DEBUG
 
         weight_t GetCost(BasicBlock* block, BasicBlock* next);
-        weight_t GetPartitionCostDelta(unsigned s1Start, unsigned s2Start, unsigned s3Start, unsigned s3End, unsigned s4End);
+        weight_t GetPartitionCostDelta(unsigned s2Start, unsigned s3Start, unsigned s3End, unsigned s4End);
         void SwapPartitions(unsigned s1Start, unsigned s2Start, unsigned s3Start, unsigned s3End, unsigned s4End);
 
-        void ConsiderEdge(FlowEdge* edge);
+        template <bool addToQueue = true>
+        bool ConsiderEdge(FlowEdge* edge);
         void AddNonFallthroughSuccs(unsigned blockPos);
         void AddNonFallthroughPreds(unsigned blockPos);
         bool RunGreedyThreeOptPass(unsigned startPos, unsigned endPos);
 
+        bool CompactHotJumps();
         bool RunThreeOpt();
 
     public:
         ThreeOptLayout(Compiler* comp);
         void Run();
     };
 
-    template <bool hasEH>
-    void fgMoveHotJumps();
-
     bool fgFuncletsAreCold();
 
     PhaseStatus fgDetermineFirstColdBlock();