Revert of [turbofan] remove control field from instruction

src/compiler/register-allocator.cc

Index: src/compiler/register-allocator.cc
diff --git a/src/compiler/register-allocator.cc b/src/compiler/register-allocator.cc
index 1c638fc655c3c113474583eed12150cb333075bb..416b970865f6bd95d9bdfee0bb90c8b2775bb320 100644
--- a/src/compiler/register-allocator.cc
+++ b/src/compiler/register-allocator.cc
@@ -2389,11 +2389,9 @@
   if (pos.Value() <= range->Start().Value()) return range;
 
   // We can't properly connect liveranges if split occured at the end
-  // a block.
+  // of control instruction.
   DCHECK(pos.IsInstructionStart() ||
-         code()
-                 ->GetInstructionBlock(pos.InstructionIndex())
-                 ->last_instruction_index() != pos.InstructionIndex());
+         !InstructionAt(pos.InstructionIndex())->IsControl());
 
   int vreg = GetVirtualRegister();
   if (!AllocationOk()) return nullptr;