Revert of [turbofan] Add alignment parameter to StackSlot operator

src/compiler/mips64/instruction-selector-mips64.cc

Index: src/compiler/mips64/instruction-selector-mips64.cc
diff --git a/src/compiler/mips64/instruction-selector-mips64.cc b/src/compiler/mips64/instruction-selector-mips64.cc
index cc1323162ca3a6c3f86704bfc52a1e73ef92ea7f..0aa4f1837b601f8a5b2fce152f92febfac50425d 100644
--- a/src/compiler/mips64/instruction-selector-mips64.cc
+++ b/src/compiler/mips64/instruction-selector-mips64.cc
@@ -350,17 +350,6 @@
 static void VisitBinop(InstructionSelector* selector, Node* node,
                        InstructionCode opcode) {
   VisitBinop(selector, node, opcode, false, kArchNop);
-}
-
-void InstructionSelector::VisitStackSlot(Node* node) {
-  StackSlotRepresentation rep = StackSlotRepresentationOf(node->op());
-  int alignment = rep.alignment();
-  int slot = frame_->AllocateSpillSlot(rep.size(), alignment);
-  OperandGenerator g(this);
-
-  Emit(kArchStackSlot, g.DefineAsRegister(node),
-       sequence()->AddImmediate(Constant(slot)),
-       sequence()->AddImmediate(Constant(alignment)), 0, nullptr);
 }
 
 void EmitLoad(InstructionSelector* selector, Node* node, InstructionCode opcode,