Use compression for mDNS NSEC record data

Although RFC3845 2.1.1 specifies that NSEC records should not use
compression for the Next DomainName field, RFC6762 18.14 specifies that
compression should also be used for NSEC RDATA. The legacy mDNS
implementation does use compression for that field.

Bug: 241738458
Test: atest
Change-Id: I9cd2b8618b01bb569a7f1d13dc3bfd09a0433300
2 files changed