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

src/arm/macro-assembler-arm.cc

Index: src/arm/macro-assembler-arm.cc
diff --git a/src/arm/macro-assembler-arm.cc b/src/arm/macro-assembler-arm.cc
index 7d9af7c051628c02b7965cf499f92ff96402f692..b76447438204b7ebe09a039a9d9eb15d1621c7bc 100644
--- a/src/arm/macro-assembler-arm.cc
+++ b/src/arm/macro-assembler-arm.cc
@@ -3653,7 +3653,7 @@ void MacroAssembler::EmitSeqStringSetCharCheck(Register string,
   cmp(index, ip);
   Check(lt, kIndexIsTooLarge);
 
-  cmp(index, Operand(Smi::FromInt(0)));
+  cmp(index, Operand(Smi::kZero));
   Check(ge, kIndexIsNegative);
 
   SmiUntag(index, index);
@@ -3943,7 +3943,7 @@ void MacroAssembler::CheckEnumCache(Label* call_runtime) {
 
   // For all objects but the receiver, check that the cache is empty.
   EnumLength(r3, r1);
-  cmp(r3, Operand(Smi::FromInt(0)));
+  cmp(r3, Operand(Smi::kZero));
   b(ne, call_runtime);
 
   bind(&start);