[NTOS:SE] Remove redundant ReturnLength NULL check

[NTOS:SE] Remove redundant ReturnLength NULL check

In NtQueryInformationToken function, remove the useless and redundant NULL check for two primary reasons. First, DefaultQueryInfoBufferCheck already does the necessary probing validation checks and second, ReturnLength must NEVER be NULL!
If the caller does not respect the calling rules of NtQueryInformationToken, the caller is expected to be miserably punished.