Resolves #329951
    Summary: MMR: Supplier does not respond anymore after many operations (deletes)
    Description: introduce OP_FLAG_REPL_RUV.  It's set in repl5_replica.c if the
    entry is RUV.  The operation should not be blocked at the backend SERIAL lock
    (this is achieved by having OP_FLAG_REPL_FIXUP set in the operation flag).
    But updating RUV has nothing to do with VLV, thus if the flag is set, it skips
    the VLV indexing.