Revert of [turbofan] Add alignment parameter to StackSlot operator

src/compiler/x87/instruction-selector-x87.cc

Index: src/compiler/x87/instruction-selector-x87.cc
diff --git a/src/compiler/x87/instruction-selector-x87.cc b/src/compiler/x87/instruction-selector-x87.cc
index b5594b8894e658d462a4ae85e629b9e57fe788e3..c11ac287d0d25fb2c5f58d1bfd49d5f553e452db 100644
--- a/src/compiler/x87/instruction-selector-x87.cc
+++ b/src/compiler/x87/instruction-selector-x87.cc
@@ -168,14 +168,6 @@
   }
 };
 
-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 InstructionSelector::VisitLoad(Node* node) {
   LoadRepresentation load_rep = LoadRepresentationOf(node->op());