[NFC][sanitizer] Add entry point for compression

Add Compression::Test type which just pretends packing,
but does nothing useful. It's only called from test for now.

Depends on D114493.

Reviewed By: kstoimenov

Differential Revision: https://reviews.llvm.org/D114494

GitOrigin-RevId: 7c1d77798346ed49fe940c651668ee922f2976e9
4 files changed