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

src/builtins/builtins-math.cc

Index: src/builtins/builtins-math.cc
diff --git a/src/builtins/builtins-math.cc b/src/builtins/builtins-math.cc
index e8d429ebac92d969e09d5fc6b7dbeee056627e2b..6058f12265a36fd3380f02ebf3e07865c0a905e6 100644
--- a/src/builtins/builtins-math.cc
+++ b/src/builtins/builtins-math.cc
@@ -316,7 +316,7 @@ void Builtins::Generate_MathFround(CodeStubAssembler* assembler) {
 BUILTIN(MathHypot) {
   HandleScope scope(isolate);
   int const length = args.length() - 1;
-  if (length == 0) return Smi::FromInt(0);
+  if (length == 0) return Smi::kZero;
   DCHECK_LT(0, length);
   double max = 0;
   bool one_arg_is_nan = false;
@@ -345,7 +345,7 @@ BUILTIN(MathHypot) {
   }
 
   if (max == 0) {
-    return Smi::FromInt(0);
+    return Smi::kZero;
   }
   DCHECK_GT(max, 0);