Implement flooring division by a constant via truncating division by a constant.

src/a64/lithium-a64.h

Index: src/a64/lithium-a64.h
diff --git a/src/a64/lithium-a64.h b/src/a64/lithium-a64.h
index a100da84ed065adcdbe672bfa068273d10185860..1bd1b80dcbd62ca76dd0d6899c0b3e3507947638 100644
--- a/src/a64/lithium-a64.h
+++ b/src/a64/lithium-a64.h
@@ -1956,16 +1956,17 @@ class LFlooringDivByPowerOf2I V8_FINAL : public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LFlooringDivByConstI V8_FINAL : public LTemplateInstruction<1, 1, 0> {
+class LFlooringDivByConstI V8_FINAL : public LTemplateInstruction<1, 1, 2> {
  public:
-  LFlooringDivByConstI(LOperand* dividend, int32_t divisor) {
+  LFlooringDivByConstI(LOperand* dividend, int32_t divisor, LOperand* temp) {
     inputs_[0] = dividend;
     divisor_ = divisor;
+    temps_[0] = temp;
   }
 
   LOperand* dividend() { return inputs_[0]; }
   int32_t divisor() const { return divisor_; }
-  LOperand* temp1() { return temps_[0]; }
+  LOperand* temp() { return temps_[0]; }
 
   DECLARE_CONCRETE_INSTRUCTION(FlooringDivByConstI, "flooring-div-by-const-i")
   DECLARE_HYDROGEN_ACCESSOR(MathFloorOfDiv)