Add binary conformance test for default repeated fields (#6440)

* Add binary conformance test for default repeated fields

1) Both packed and unpacked encoding should be accepted for parsing.
2) Encode should follow the default way for the syntax.

* Uncomment test

* Remove is_primitive

* Add failed tests to failure lists.

* Add failed test to failure list

* Use binary format to specify expected value

Text format cannot distinguish whether repeated field is packed or not.

* Change method name from ToHexString to ToOctString

* Add failed test to failure list

* Add failed test to php's failure list

* Fix comments