[turbofan] Reland of `Add alignment parameter to StackSlot operator`

src/compiler/instruction-selector.cc

Index: src/compiler/instruction-selector.cc
diff --git a/src/compiler/instruction-selector.cc b/src/compiler/instruction-selector.cc
index 42bb7b74d84a870d40f8979d9ba7c20ea091952b..e545d810a75823a79820a9797fa69b0421b17b81 100644
--- a/src/compiler/instruction-selector.cc
+++ b/src/compiler/instruction-selector.cc
@@ -1900,14 +1900,6 @@ void InstructionSelector::EmitLookupSwitch(const SwitchInfo& sw,
   Emit(kArchLookupSwitch, 0, nullptr, input_count, inputs, 0, nullptr);
 }
 
-void InstructionSelector::VisitStackSlot(Node* node) {
-  int size = StackSlotSizeOf(node->op());
-  int slot = frame_->AllocateSpillSlot(size);
-  OperandGenerator g(this);
-
-  Emit(kArchStackSlot, g.DefineAsRegister(node),
-       sequence()->AddImmediate(Constant(slot)), 0, nullptr);
-}
 
 void InstructionSelector::VisitBitcastTaggedToWord(Node* node) {
   EmitIdentity(node);