Revert of [turbofan] Add alignment parameter to StackSlot operator

src/compiler/arm64/instruction-selector-arm64.cc

Index: src/compiler/arm64/instruction-selector-arm64.cc
diff --git a/src/compiler/arm64/instruction-selector-arm64.cc b/src/compiler/arm64/instruction-selector-arm64.cc
index 0e9fd0ca2b548d963e24bdbd9cfbba7a9e7646a2..d9f972e81ccb34ef5154940e248f74d9ddb6dd6f 100644
--- a/src/compiler/arm64/instruction-selector-arm64.cc
+++ b/src/compiler/arm64/instruction-selector-arm64.cc
@@ -526,15 +526,6 @@
 }
 
 }  // namespace
-
-void InstructionSelector::VisitStackSlot(Node* node) {
-  StackSlotRepresentation rep = StackSlotRepresentationOf(node->op());
-  int slot = frame_->AllocateSpillSlot(rep.size());
-  OperandGenerator g(this);
-
-  Emit(kArchStackSlot, g.DefineAsRegister(node),
-       sequence()->AddImmediate(Constant(slot)), 0, nullptr);
-}
 
 void EmitLoad(InstructionSelector* selector, Node* node, InstructionCode opcode,
               ImmediateMode immediate_mode, MachineRepresentation rep,