Use ::int32_t to avoid confusion with bad field names.

Packed repeated fields without cached_size use static_cast<int32_t> that may be confused
with bad field names. This change fixes it by using ::int32_t.

PiperOrigin-RevId: 693884622

src/google/protobuf/compiler/cpp/field_generators/enum_field.cc

@@ -535,7 +535,7 @@ void RepeatedEnum::GenerateByteSize(io::Printer* p) const {
                  data_size == 0
                      ? 0
                      : $kTagBytes$ + ::_pbi::WireFormatLite::Int32Size(
-                                         static_cast<int32_t>(data_size));
+                                         static_cast<::int32_t>(data_size));
                )cc");
              } else {
                p->Emit(R"cc(

src/google/protobuf/compiler/cpp/field_generators/primitive_field.cc

@@ -625,7 +625,7 @@ void RepeatedPrimitive::GenerateByteSize(io::Printer* p) const {
                  data_size == 0
                      ? 0
                      : $kTagBytes$ + ::_pbi::WireFormatLite::Int32Size(
-                                         static_cast<int32_t>(data_size));
+                                         static_cast<::int32_t>(data_size));
                )cc");
              } else {
                p->Emit(R"cc(