java log config always using the `java_instance_log4j.xml` when the `java.Log.LogConfig` is set

[jiangpengcheng]

for example, with below java log config:

java:
  log:
    javaLog4JConfigFileType: yaml
    logConfig:
        key: log.yaml
        name: mylog

the correct way is to use java_instance_log4j.yaml as the -Dpulsar.function.log.file, but it still use the java_instance_log4j.xml