Revert "Default to packed repeated primitive fields in proto3."

This reverts commit 1467b81.

Author: stepancheg

protobuf-codegen/src/gen/field/mod.rs

@@ -188,36 +188,7 @@ impl<'a> FieldGen<'a> {
 
                 FieldKind::Repeated(RepeatedField {
                     elem,
-                    packed: field
-                        .field
-                        .proto()
-                        .options
-                        .get_or_default()
-                        .packed
-                        .unwrap_or(match field.message.scope.file_scope.syntax() {
-                            Syntax::Proto2 => false,
-                            // in proto3, repeated primitive types are packed by default
-                            Syntax::Proto3 => match field.field.proto().type_() {
-                                Type::TYPE_DOUBLE
-                                | Type::TYPE_FLOAT
-                                | Type::TYPE_INT64
-                                | Type::TYPE_UINT64
-                                | Type::TYPE_INT32
-                                | Type::TYPE_FIXED64
-                                | Type::TYPE_FIXED32
-                                | Type::TYPE_BOOL
-                                | Type::TYPE_UINT32
-                                | Type::TYPE_SFIXED32
-                                | Type::TYPE_SFIXED64
-                                | Type::TYPE_SINT32
-                                | Type::TYPE_SINT64 => true,
-                                Type::TYPE_STRING
-                                | Type::TYPE_GROUP
-                                | Type::TYPE_MESSAGE
-                                | Type::TYPE_BYTES
-                                | Type::TYPE_ENUM => false,
-                            },
-                        }),
+                    packed: field.field.proto().options.get_or_default().packed(),
                 })
             }
             RuntimeFieldType::Singular(..) => {