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

src/mips/macro-assembler-mips.cc

Index: src/mips/macro-assembler-mips.cc
diff --git a/src/mips/macro-assembler-mips.cc b/src/mips/macro-assembler-mips.cc
index d61717d22257909d844f297cb65b48cea4777b72..ac1bf10411e89ecf5af0747af90725b1f43e6735 100644
--- a/src/mips/macro-assembler-mips.cc
+++ b/src/mips/macro-assembler-mips.cc
@@ -6473,7 +6473,7 @@ void MacroAssembler::EmitSeqStringSetCharCheck(Register string,
   lw(at, FieldMemOperand(string, String::kLengthOffset));
   Check(lt, kIndexIsTooLarge, index, Operand(at));
 
-  DCHECK(Smi::FromInt(0) == 0);
+  DCHECK(Smi::kZero == 0);
   Check(ge, kIndexIsNegative, index, Operand(zero_reg));
 
   SmiUntag(index, index);
@@ -6733,7 +6733,7 @@ void MacroAssembler::CheckEnumCache(Label* call_runtime) {
 
   // For all objects but the receiver, check that the cache is empty.
   EnumLength(a3, a1);
-  Branch(call_runtime, ne, a3, Operand(Smi::FromInt(0)));
+  Branch(call_runtime, ne, a3, Operand(Smi::kZero));
 
   bind(&start);