Add Smi::Zero and replace all Smi::FromInt(0) calls

src/full-codegen/arm64/full-codegen-arm64.cc

Index: src/full-codegen/arm64/full-codegen-arm64.cc
diff --git a/src/full-codegen/arm64/full-codegen-arm64.cc b/src/full-codegen/arm64/full-codegen-arm64.cc
index bf157476d486ded1823a229d5a99ee2493ceea30..ffd2b0c09ffa3be1d9e8603504e12d49ca131e1c 100644
--- a/src/full-codegen/arm64/full-codegen-arm64.cc
+++ b/src/full-codegen/arm64/full-codegen-arm64.cc
@@ -357,11 +357,7 @@ void FullCodeGenerator::Generate() {
   masm()->CheckConstPool(true, false);
 }
 
-
-void FullCodeGenerator::ClearAccumulator() {
-  __ Mov(x0, Smi::FromInt(0));
-}
-
+void FullCodeGenerator::ClearAccumulator() { __ Mov(x0, Smi::kZero); }
 
 void FullCodeGenerator::EmitProfilingCounterDecrement(int delta) {
   __ Mov(x2, Operand(profiling_counter_));