This series gets rid of the remaining usage of flat_mutation_reader v1 in compaction
Test: sstable_compaction_test
Closes#10454
* github.com:scylladb/scylla:
compaction: sanitize headers from flat_mutation_reader v1
flat_mutation_reader: get rid of class filter
compaction: cleanup_compaction: make_partition_filter: return flat_mutation_reader_v2::filter
The only user is the tests of downgrade_to_v1(), which uses it through
mutation source. To avoid any new users popping up, we make it a private
method of the latter. In the process the pass-through optimization is
dropped, it is not needed for tests anyway.
The flat_mutation_reader files were conflated and contained multiple
readers, which were not strictly necessary. Splitting optimizes both
iterative compilation times, as touching rarely used readers doesn't
recompile large chunks of codebase. Total compilation times are also
improved, as the size of flat_mutation_reader.hh and
flat_mutation_reader_v2.hh have been reduced and those files are
included by many file in the codebase.
With changes
real 29m14.051s
user 168m39.071s
sys 5m13.443s
Without changes
real 30m36.203s
user 175m43.354s
sys 5m26.376s
Closes#10194
