[turbofan] More thorough validation of LiveRanges.

src/compiler/register-allocator.h

Index: src/compiler/register-allocator.h
diff --git a/src/compiler/register-allocator.h b/src/compiler/register-allocator.h
index 6437cebc485b8421473bf84a55c907365a77ecce..3e8e43233fd9fa1776c2df8cae2bb1229044ee2b 100644
--- a/src/compiler/register-allocator.h
+++ b/src/compiler/register-allocator.h
@@ -396,7 +396,10 @@ class LiveRange : public ZoneObject {
   bool Covers(LifetimePosition position) const;
   LifetimePosition FirstIntersection(LiveRange* other) const;
 
-  void Verify() const;
+  void VerifyChildStructure() const {
+    VerifyIntervals();
+    VerifyPositions();
+  }
 
   void ConvertUsesToOperand(const InstructionOperand& op,
                             const InstructionOperand& spill_op);
@@ -428,6 +431,9 @@ class LiveRange : public ZoneObject {
   void AdvanceLastProcessedMarker(UseInterval* to_start_of,
                                   LifetimePosition but_not_past) const;
 
+  void VerifyPositions() const;
+  void VerifyIntervals() const;
+
   typedef BitField<bool, 0, 1> SpilledField;
   typedef BitField<int32_t, 6, 6> AssignedRegisterField;
   typedef BitField<MachineRepresentation, 12, 8> RepresentationField;
@@ -590,6 +596,9 @@ class TopLevelLiveRange final : public LiveRange {
   int debug_virt_reg() const;
 #endif
 
+  void Verify() const;
+  void VerifyChildrenInOrder() const;
+
   int GetNextChildId() {
     return IsSplinter() ? splintered_from()->GetNextChildId()
                         : ++last_child_id_;