fix(utils): fix bug in time_utils

[levy5307]

There is a function in time_utils, which name is get_localtime. It calls localtime_r(const time_t *timep, struct tm *result) and return the return value of this function.
While localtime_r needs the second parameter, the struct tm *result, as a buffer to store the return value. But in our get_localtime function, it pass a local variable to localtime_r. And after it returns, the local variable is destroyed. So this leads to some undefined errors.

[levy5307]

本来为time_ms_to_string/time_ms_to_date/time_ms_to_date_time/time_ms_to_date_time这四个function添加了单测的，后来发现由于github上ci和本地时区不一样，导致转换出来的时间不一样，这样ci上单测跑不过