[runtime] Optimize and unify rest parameters.

src/globals.h

Index: src/globals.h
diff --git a/src/globals.h b/src/globals.h
index b1ff6c5f5ddaa386e2820310f818305d15d74cb2..d1cae952a827175c5256da59362eaae411af9482 100644
--- a/src/globals.h
+++ b/src/globals.h
@@ -770,6 +770,30 @@ inline std::ostream& operator<<(std::ostream& os, TailCallMode mode) {
   return os;
 }
 
+// Defines specifics about arguments object or rest parameter creation.
+enum class CreateArgumentsType : uint8_t {
+  kMappedArguments,
+  kUnmappedArguments,
+  kRestParameter
+};
+
+inline size_t hash_value(CreateArgumentsType type) {
+  return bit_cast<uint8_t>(type);
+}
+
+inline std::ostream& operator<<(std::ostream& os, CreateArgumentsType type) {
+  switch (type) {
+    case CreateArgumentsType::kMappedArguments:
+      return os << "MAPPED_ARGUMENTS";
+    case CreateArgumentsType::kUnmappedArguments:
+      return os << "UNMAPPED_ARGUMENTS";
+    case CreateArgumentsType::kRestParameter:
+      return os << "REST_PARAMETER";
+  }
+  UNREACHABLE();
+  return os;
+}
+
 // Used to specify if a macro instruction must perform a smi check on tagged
 // values.
 enum SmiCheckType {