Consistently use a separate Lithium instruction for flooring division.

src/arm64/lithium-arm64.h

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1306 matching lines @@
   DECLARE_CONCRETE_INSTRUCTION(DivByConstI, "div-by-const-i")
   DECLARE_HYDROGEN_ACCESSOR(Div)
 
  private:
   int32_t divisor_;
 };
 
 
 class LDivI V8_FINAL : public LTemplateInstruction<1, 2, 1> {
  public:
-  LDivI(LOperand* left, LOperand* right, LOperand* temp) {
-    inputs_[0] = left;
-    inputs_[1] = right;
+  LDivI(LOperand* dividend, LOperand* divisor, LOperand* temp) {
+    inputs_[0] = dividend;
+    inputs_[1] = divisor;
     temps_[0] = temp;
   }
 
-  LOperand* left() { return inputs_[0]; }
-  LOperand* right() { return inputs_[1]; }
+  LOperand* dividend() { return inputs_[0]; }
+  LOperand* divisor() { return inputs_[1]; }
   LOperand* temp() { return temps_[0]; }
 
   DECLARE_CONCRETE_INSTRUCTION(DivI, "div-i")
   DECLARE_HYDROGEN_ACCESSOR(BinaryOperation)
 };
 
 
 class LDoubleToIntOrSmi V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LDoubleToIntOrSmi(LOperand* value) {
@@ skipping 1746 matching lines @@
 
   DISALLOW_COPY_AND_ASSIGN(LChunkBuilder);
 };
 
 #undef DECLARE_HYDROGEN_ACCESSOR
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_ARM64_LITHIUM_ARM64_H_