Remove inclusion of ext/json/php_json.h. (#3241)
Remove inclusion of ext/json/php_json.h. (#3241)

That implementation of json is not being used - this extension is using
a json encoder/decoder provided by 'upb'.
google/protobuf,google/protobuf,google/protobuf,google/protobuf,google/protobuf,google/protobuf,google/protobuf,google/protobuf,google/protobuf,google/protobuf,google/protobuf