[llvm] [NFC] Various Cleanup in StackColoring, StackSlotColoring, LiveStacks (PR #143931)

[Matt Arsenault via llvm-commits]

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@@ -561,8 +580,15 @@ LLVM_DUMP_METHOD void StackColoring::dump() const {
 
 LLVM_DUMP_METHOD void StackColoring::dumpIntervals() const {
   for (unsigned I = 0, E = Intervals.size(); I != E; ++I) {
-    dbgs() << "Interval[" << I << "]:\n";
+    dbgs() << "Interval[" << I << "]:";
+    if (MFI->getObjectAllocation(I))
+      dbgs() << *MFI->getObjectAllocation(I);
+    dbgs() << "\n";
     Intervals[I]->dump();
+    dbgs() << "LiveStarts:";
+    for (SlotIndex SIdx : LiveStarts[I])
+      dbgs() << " " << SIdx;
+    dbgs() << "\n";
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arsenm wrote:

```suggestion
      dbgs() << ' ' << SIdx;
    dbgs() << '\n';
```

https://github.com/llvm/llvm-project/pull/143931